Ljubljana, Slovenia – private cars and public transport
"Intelligent Transport Systems" (ITS) is a generic term for the integrated application of communications, control and information processing technologies to the transport system. The resulting benefits save lives, time, money, energy and the environment and stimulate economic performance.
ITS covers all modes of transport and considers all elements – the vehicles, the infrastructure, the drivers and users – all interacting together dynamically.
The main function of ITS is to provide services and information for the full spectrum of users – in particular drivers, passengers, vehicle owners and operators, but also vulnerable road users like pedestrians and cyclists – and support safe and efficient traffic management by the transport network operators. The intention is to improve the operation of the entire transport system. With ITS, road users such as motorists, freight and commercial fleet operators and public transport customers can make better judgements on their travel decisions. Factors such as traffic conditions, road maintenance or construction work may potentially impact on travel times; weather conditions will affect the road network and safety.
ITS provides better quality and diversity of information on road and traffic conditions, often in real-time. The use of ITS in Road Network Operations (RNO) also makes it possible to improve existing operating strategies and devise new ways of managing road traffic.
Intelligent Transport Systems (abbreviated to I.T.S. and written ITS) refers to the use of information and communication technologies in transport. The development of ITS is still evolving. The extent to which these technologies are used – and the degree of sophistication in their deployment – varies from one country to another. Transport professionals around the globe need to understand the principal applications and capabilities of ITS so they can assess potential advantages, associated costs and how ITS may best be deployed.
Intelligent Transport Systems (ITS) are the control and information systems that use integrated communications and data processing technologies for the purposes of:
The definition covers a broad array of techniques and approaches that may be achieved through stand-alone technological applications or through integration of different systems to provide new (or enhancements to) existing transport services. ITS provides the tools to transform mobility and improve safety – and is particularly relevant in the context of road network operations.
ITS aims to serve the user of the transport system by providing– for the individual – more reliability and comfort for individual mobility and – for the operator of the transport system – more effective operations and decision making. The overall function of ITS is to improve the operation of the entire transport system (often in real-time) for transport network controllers, travellers, shippers and other users.
ITS deployment is influenced by commercial interests and policy initiatives at the international, national, regional and local level – which impact on the business practices of stakeholders in the public or private sector.
ITS provides a flexible approach to addressing common transport problems – one that emphasises the use of information, optimal decision-making and a high level of system adaptability. This compares with the more traditional approach of building additional road infrastructure and adding physical capacity. ITS offers alternatives to meeting future travel demand in situations where conventional approaches may not work – for example in heavily built-up locations or in areas subject to stringent environmental regulations.
More specifically, ITS includes a variety of tools, such as sensing, communications, and computing technologies – which can be applied in an integrated way to the transport system to improve its efficiency, safety, sustainability and the resilience of network operations in the events of serious disruption.
ITS has the potential to relive some of the most difficult problems that affect road transport today. In general ITS applications have the capability to:
ITS can also make travel more convenient by providing travellers with accurate and timely information about the traffic conditions on the network, and available transport options. It can also foster economic growth in a region, by improving mobility, enhancing travel time reliability and reducing energy consumption.
Many ITS applications have a role to play in effective road network operations – the aims of which include:
In general, ITS applications that are designed to improve the efficiency, safety and/or sustainability of road networks are the applications most frequently adopted. Examples include:
The concept of connected autonomous vehicles is becoming feasible and gaining support which will have major implications for road network operations – which will need full evaluation. (See Driver Support)
Video: Austria ITS FOCUS: Traffic Management and Control
All road users, including drivers and their passengers, pedestrians and cyclists – across all modes of road transport, including private cars, buses, coaches and commercial vehicles – can benefit from greater use of ITS. For example, ITS applications support:
The use of technology to manage transport systems, and to improve their efficiency and safety, has a long history that predates the first use of the term “ITS” in the 1990s.
Among the first examples of technology applied to road transport were urban traffic signal control systems – with increasing levels of sophistication over time (in terms of sensing vehicle presence and control logic). Their purpose was to control traffic at road intersections to improve traffic flow and safety. Other early ITS applications were for motorway incident detection and improving the information available for travellers – with real-time traffic alerts and roadside Variable Message Signs. (See Traffic Control)
In the 1990s, there was increased recognition of the negative impacts of road transport (such as congestion, accidents and pollution) and the search began for solutions to the challenges that facing large, congested, metropolitan areas. The traditional solution of adding capacity by improving the road infrastructure was often no longer viable – for example, because of environmental concerns or the unavailability of space. These factors combined to motivate transport professionals to investigate the potential for utilising advanced technologies – such as sensing, communications and computing – to improve the performance of road networks.
ITS deployment is now almost ubiquitous in developed countries and has begun to take root in many emerging economies as well. The range of potential applications for ITS, has dramatically increased. Whereas initially the focus was on stand-alone applications, there are now examples of truly integrated systems – solutions that look at the transport system as an integrated whole – for example, integrated multimodal ticketing. (See Multiuse/Intermodal Ticketing)
The early years of ITS were championed by a handful of countries – including the United States, Canada, a number of European countries, Japan and Australia. In the USA, for example, several transport reauthorisation bills – from the 1991 Intermodal Surface Transportation Efficiency Act (or ISTEA) onwards, encouraged the deployment of ITS and the search for advanced technology applications in transport. A number of Field Operational Tests (FOT) were also undertaken – designed to test the feasibility of implementing the technology-based solutions, as well as provide information on their likely costs and benefits.
A decade or so ago the means for disseminating information to travellers were rather limited (such as Dynamic Variable Message Signs, Highway Advisory Radio, Television, and phone systems). Today, with the almost universal market penetration of smart phones and other mobile devices, it is much easier to reach travellers with the correct information. (See Traveller Services)
Recent years have witnessed a renewed and increased interest in the topic of connected and autonomous (self-driving) vehicles – which can be regarded as the latest phase in the evolution of ITS. Third and fourth generation digital mobile telecommunications have enabled higher levels of connectivity between vehicles and the infrastructure, coupled with greater automation within vehicles. This may radically change the way that motor vehicles are driven and the way that road traffic is managed. (See Connected Vehicles)
ITS service Areas
The principal applications of ITS – that contribute to road network operations are:
The table below illustrates the eight main ITS service areas – and provides examples of service applications in those areas.
Service Area | ITS Related Applications | Operational Goal |
---|---|---|
Traffic management |
Incident management; traffic control. |
Manage and control traffic on roadways to optimize its operation. |
Traveller information |
Pre-trip traveller information, en-route traveller information. |
Provide trip related information to travellers before, or during their trips |
Public transport |
Transit vehicle tracking; transit security. |
Improve public transport services to encourage their use |
Commercial vehicle operations |
Commercial vehicle administrative processes, Automated roadside safety inspection, hazardous material incident response |
Improve public sector fleet management; improve public sector administration of commercial vehicle operations |
Vehicle safety |
Vision enhancement, longitudinal and lateral crash avoidance; intersection crash avoidance. |
Improve the safety of the transport system by supplementing drivers’ abilities to maintain alertness and control of the vehicle, and enhancing crash avoidance capabilities of vehicles |
Construction and maintenance operations |
Fleet management; work zone management. |
Improve management of vehicles associated with construction and maintenance; managing work zones, managing roadways for supporting construction and maintenance |
Emergency management |
Emergency notification; emergency vehicle management. |
Support emergency management functions with faster identification of emergencies and response |
Archived Data Management |
Data depository |
Collect and compile data for traffic prediction, system performance monitoring and policy analysis |
ITS-based services share some general characteristics:
Time is a critical element in ITS services which often make use of real-time or near real-time data. The time frame for collecting and processing live data is limited, although historical data is frequently used. For example, traffic information – such as travel time, link speed and information about incidents blocking lanes – is only useful to travellers if it is made available in real-time or predicted near-future time. (See Traveller Services)
Many ITS services can enhance the capacity of existing road infrastructure by means of operational improvements that avoid the need for expenditure on major improvements – such as constructing new roads or adding additional lanes. For example, on congested motorways – managed lanes and speed control can benefit safety leading to fewer traffic incidents and improved traffic throughput. Strategic re-routing can divert traffic from congested roads to less congested roads at certain times of the day. Traffic signals can be made to be adaptive to real-time traffic demands to improve efficiency and capacity of signalized intersections.
Data collected through ITS – such as traffic speed, traffic volume and vehicle tracking data – can be used for real-time decision support for individual travellers, road network operators and vehicle fleet managers. Data collected through ITS can also be used in algorithms and models that assess current and future network conditions – which provide decision support. Data collected through ITS can also be archived until needed for planning purposes.
ITS services are most valuable and effective in unfavourable conditions – such as during an incident, evacuation, congestion or disruption of services. For example, an incident may cause significant delays and contribute to secondary traffic accidents. ITS services – such as quick detection of an incident, faster response and incident scene management – may reduce the duration of an incident, which will contribute to reductions in traffic delays and a lower probability of secondary accidents.
ITS provides an opportunity to enhance reliability and safety of a trip. ITS services – such as satellite navigation, incident management and adaptive traffic signal control – can reduce delays and improve the reliability of a trip. Similarly, ITS services geared towards safety – such as speed warning and enforcement and intersection collision avoidance – can decrease the probability of an accident.
ITS services have been developed for more than one mode of transport – and can target different types of vehicle. For example, roadway network monitoring services keep track of passenger cars, buses, emergency vehicles and commercial vehicles. ITS services can also determine priority routing for specific vehicle types – for example, buses and coaches can be prioritised with a green light at traffic signals along a corridor. Similarly, signal pre-emption technology can allow emergency vehicles to receive -of-way through an intersection by directly communicating with the traffic signal control equipment.
Miles J.C. (2014) Intelligent Transport Systems: Overview and Structure (History, Applications, and Architectures). Automotive Encyclopedia ISBN: 9781118354179 Wiley on-line Library.
Table of contents can be accessed on-line at: http://onlinelibrary.wiley.com/book/10.1002/9781118354179/toc
A common feature of ITS – when applied to traffic and road network management – is the use of real-time, conventional and historic data sources to produce information on the existing and future status of the road transport system. ITS applications play an important part in the way road networks are managed to improve the efficiency and reliability of transport operations and reduce negative environmental and energy consumption impacts. (See Traffic Management)
Examples of ITS applications in road network operations are:
Traffic and road network management applications aimed at improving road transport efficiency includes electronic payment to remove the need for vehicles to come to halt before paying a road toll and to simplify fare payment for public transport. (See Case Study: Traffic Management, Travel Information and Bridge Tolling at “The Ǿresund Link”)
Electronic tolling systems also provide the flexibility needed to implement innovative road pricing and congestion charge schemes.
The principal ITS applications that support traffic and road network management include:
Traffic control aims to manage and control the movement of traffic on roads to optimise the use of existing road capacity. ITS applications include:
The implementation of effective traffic control strategies requires timely and accurate traffic information. The better the data, the more effective the control strategies that can be implemented. Information is gathered from various sources – such as detector loops in the road pavement, roadside and overhead sensors and analysis of digital camera images. The data can be combined and used to decide upon the best (or optimal) course of action for managing traffic on the network. (See Traffic Control)
Traffic control is one of the most basic building blocks of an intelligent road transport system, since it requires detection, control, communications and support systems – that are fundamental to the operation of several other ITS services. Traffic control and traffic operations centres (TCCs and TOCs), responsible for these functions, now exist all over the world. (See Traffic Control Centres)
ITS plays a significant role in improving incident management, particularly on highways, motorways and other high speed roads. This is because it uses vehicle sensors (such as inductive, buried, loops, radar and CCTV cameras), data processing and communications technologies to quickly detect and verify an incident. Sophisticated decision support systems then help traffic managers to decide how to best respond to any given incident. Using ITS in this way can improve safety and network efficiency, saving lives and money. (See Traffic Incidents)
One of the application areas where ITS has achieved great success is in the area of electronic payment. Among the prime examples of electronic payment are Electronic Toll Collection (ETC) systems such as the EZPass System in the USA or the European Electronic Toll Service. These systems allow drivers to pay road tolls without stopping or slowing down their travel speed – minimising delays and improving air quality in the vicinity of toll plazas.
ETC systems can take various forms such as:
These systems can impose different tolls for different classes of vehicles, and can provide for the automatic enforcement of violations. Other examples include integrated payment systems – designed to allow a traveller to pay for different services (for example driving on a toll road, paying for parking, paying for transit) using the same medium or device (See Electronic Payment).
ITS can be applied to implement strategies aimed at increasing the frequency of Multiple-Occupancy Vehicles (MOVs) and promoting the use of High-Occupancy Vehicle lanes (HOVs). ITS can help make the operation of HOV lanes more effective and adaptive to changing traffic conditions – by adjusting vehicle occupancy requirements at different times of day, based upon current traffic and congestion levels. ITS also can help implement congestion pricing strategies – where toll charges are adjusted to influence demand. For example, tolls can be increased during peak hours in urban areas or in the vicinity of environmentally sensitive tourist attractions in rural areas. (See Demand Management)
ITS can be applied to better manage the allocation and price of parking spaces. This helps improve the travel experience of drivers by providing real-time information on spaces in parking lots. ITS-based parking information systems can be integrated with city-wide traffic management and control – to minimise parking search times and optimise traffic management overall. Electronic toll tags can also be used as a means of controlling access to a controlled parking area. (See Access Control)
ITS can help improve the environmental sustainability of road transport. Some ITS applications use environmental sensors to collect information about exhaust emissions from vehicles at a certain location, or over a wide area. The information can then be used to intelligently divert traffic away from areas where air quality has fallen below an acceptable threshold – or by not letting vehicles access these environmentally sensitive areas. The information can also provide valuable input to the development of air quality improvement strategies – and to alert vehicles’ operators if their vehicles are not compliant with adopted emissions standards. ITS can also be used to manage congestion and reduce delay – which has beneficial impacts on emissions and air quality. (See Driver Support)
The purpose of a highway-rail intersection ITS application, is to provide improved warning and safety control devices where a railway (railroad) crosses a road or highway at a level crossing (an “at-grade” crossing). On the approach roads to the crossing, any signalised intersections can be connected to the control and warning devices at the highway-rail intersection (HRI), so that signals can be coordinated to manage queuing and divert traffic. The technology can also monitor the “health” of HRI equipment – and report any detected malfunctioning. (See Enforcement)
ITS system and service applications have an important role to play in emergency situations:
Emergency notification and personal security applications include systems that:
The European eCall and American OnStar systems are good examples:
Emergency vehicle management focuses on applications intended to reduce the time from the receipt of an emergency notification to the arrival of the emergency vehicle at the scene of the incident. This is accomplished through:
Traveller information systems is an application area that has seen numerous ITS developments and heavy investment. (See Traveller Services)
There are five of the leading applications:
The goal of pre-trip travel information is to provide travellers with information about the status of the transport network before they begin their trip. The information provided can be limited to road or multimodal transport – and can include:
In the early years of ITS, travellers were able to access this information at home or work (via a computer or a telephone system) and at places generating traffic (for example, a shopping mall – via a touch-screen kiosk). Nowadays, with the proliferation of smart phones and mobile devices connected to the internet, travellers can access travel information anytime, anywhere. More advanced versions of these systems can provide users with predictive travel conditions, as well as help with trip planning. (See Pre-trip Information)
En-Route driver information is aimed at providing drivers with travel-related information after they start their trip – during the journey. Traditionally, this has been achieved by means of Variable Message Signs (VMS), radio broadcasts and Highway Advisory Radio (HAR). More recently with the widespread introduction of smart phones and mobile devices – and with the interest in developing Connected Vehicles – more effective means are available to provide travel information and to personalise it for the traveller specific to the journey and locations.
The development of Connected Vehicles that will be able to communicate with the infrastructure as well as with other vehicles, will allow greater opportunity for the delivery of advisory and warning messages to drivers (for example, warning motorists of unsafe conditions such as sharp curves, wet pavements, icy conditions – and alerting motorists if they exceed the safe speed limit and alerting drivers to unsafe weather conditions.) (See En-route Information and Driver Support)
The widespread use of GPS navigation devices provides drivers with detailed turn-by-turn instructions on how to get to their destinations. These directions traditionally relied on static information – for example historic travel times for different road segments, held in a navigation database. More sophisticated guidance systems are dynamic – with directions responding to changing traffic conditions based on real-time information about traffic speeds and incident locations. The digital maps that support these device need to be kept up-to-date – for example, by downloading updates on new road links and traffic restrictions.
Route guidance is now widely available through in-vehicle systems, portable devices and smartphone handsets. The benefits include reduced travel delays arising from navigational errors and lower stress levels for drivers, especially when driving in an unfamiliar area. Problems can arise for local communities when a product – intended for the general motorist – is used by drivers of large or heavy vehicles and the recommended route is a road unsuitable for those vehicles. (See Navigation and Positioning)
Ride-matching and reservation is aimed at encouraging carpooling by providing real-time matching of the preferences and demands of users with providers – and by serving as a clearinghouse for financial transactions. A traveller can call a service centre and provide it with information about the desired trip origin, destination, and time. In return, the traveller will receive feedback on a number of ridesharing options from which to choose. (See Ride Sharing / Matching)
Traveller service information is intended to provide travellers with “yellow-pages” information. This may include information on the location of services such as food, lodging, gas stations, hospitals, police stations – as well as information on the location of points of tourist attractions. Examples of these applications are already included in many GPS navigation devices and smart phone apps. (See Location Based Services)
ITS is widely deployed to improve the level of service offered by public transport – to make buses, coaches, metros, trams and trains more convenient and encourage their greater use as a means of transport. (See Passenger Transport)
Four examples of such applications are:
Public transport management applications use advanced communications and information systems to collect data to improve the:
Real-time data collected from vehicle tracking and location systems can be used to ensure schedule adherence – and to implement corrective actions when a particular vehicle is running behind schedule. Real-time information applications can also help facilitate passengers’ transfers at connecting stations. Off-line, the data collected can be analysed and used to revise schedules, to better plan routes, to satisfy contract reporting requirements, and to improve customer information systems. (See Operations & Fleet Management)
En-route information applications are intended to provide public transport travellers with information after their trips have started. Among the key pieces of information which are typically provided are:
Various information dissemination devices could be used including signs and kiosks at bus stops, internet websites that can be accessed via smart phones and mobile devices, and various types of smart phone apps. (See Information Dissemination)
Personalised Public Transport (PPT) is based on the idea of using flexibly-routed vehicles to offer more convenient services to travellers – in some cases door-to-door. There are two main types of PPT:
Ideally, this type of application will offer journey reservations – and vehicle assignment and scheduling to be developed in real-time. (See Dynamic Routing / Scheduling)
Video: Good News tests: Kutsuplus service – personalised public transport
Public transport security ITS applications are aimed at improving the security of public transport users, operators and support staff. This can be achieved by integrating vehicle location technologies and monitoring systems to provide a warning and response system to deal with security-related incidents. For example, transport stations and terminals, parking lots, bus stops and the inside of transport vehicles can be monitored with CCTV with image processing for surveillance – so that an alarm is triggered, either manually or automatically, by an “at-risk” event. Critical infrastructure, such as bridges, tunnels, rail track, can also monitored in this way as part of a public transport security strategy. (See Network Security)
ITS has been applied to improving the efficiency and safety of commercial vehicles. (See Freight and Commercial Services) There are two broad areas of applications:
Specific examples include:
Electronic clearance is designed to allow compliant commercial vehicles to continue past checkpoints at mainline speeds. As a vehicle approaches a checkpoint, communications between the vehicle and the inspection station take place – often by means of a dedicated short-range wireless link – allowing the authorities to check relevant information, such as the vehicle’s credentials, weight, safety status and cargo. This system allows enforcement personnel to select potentially unsafe vehicles for inspection, while permitting safe vehicles to bypass the commercial vehicle checkpoint. (See Credential Checking)
As a complement to commercial vehicle electronic clearance, automated roadside safety inspection ITS applications use automated inspection capabilities to facilitate safety checks with greater speed and accuracy during a safety inspection at a vehicle inspection site. This helps reduce the amount of time spent by the vehicle examiners inspecting vehicles, whilst also providing more reliable data on the safety status of the vehicle. (See Safety Information Exchange)
Among the many ITS automotive engineering applications are systems that monitor the safety condition of a vehicle and cargo as well as the driver – without the need for the vehicle to slow down. The monitoring capabilities may include:
Safety warnings are provided to drivers and can be made available to vehicle fleet managers or controllers and to roadside enforcement personnel. (See Safety)
ITS applications can smooth the administrative processes required of commercial fleet operators by government or regulatory bodies. They may allow the automatic purchase of credentials (such as a port permit or other selective access toll) and include automated reporting of mileage and fuel use. This saves the operator time and money. (See Enforcement)
ITS has a part to play in the response to incidents involving hazardous materials (HAZMAT). Law enforcement and HAZMAT response personnel can be provided with timely, accurate information on cargo contents at the scene of an accident – so they know exactly how to handle the materials involved in an appropriate way. Emergency responders can be provided with access to this information – either through remote access to the relevant databases, or, in real-time, through the use of readers that communicate with the HAZMAT vehicle’s on-board transponder. (See Emergency Response)
ITS applications provide real-time communications between drivers, dispatchers and intermodal transport providers for the purposes of vehicle location identification, dispatching, and tracking – to help optimise freight operations and vehicle utilisation. (See Operations & Fleet Management)
A number of ITS developments in the automotive sector are focused on improving the safety of the road transport system by complementing, or enhancing, drivers’ abilities to maintain alert and in control of the vehicle – and improving the accident avoidance performance of vehicles. A major motivation in their development is recognition of driver error as a major factor in the majority of car accidents. Developments in this area are moving towards the concept of self-driving cars and automated vehicle-highway systems. Examples of this type of safety-related ITS applications include: (See Driver Support)
The automotive industry has been working on a variety of collision avoidance systems that are either already in production or close to market. (See Warning and Control) These systems include:
These systems monitor the separation distance between vehicles and warn drivers when sensors detect another vehicle that may be dangerously close. If the driver does not react appropriately, automatic vehicle control actions may be initiated. Examples of these systems are already installed in the vehicles of some automotive manufacturers, such as Mercedes and Volvo.
Advanced Emergency Braking Systems (AEBS) detect the possibility of a collision with the vehicle ahead and warn the driver – using visual, audio or tactile feedback. If the driver takes no action, the system automatically applies the vehicle's brakes. At lower speeds AEBS acts to prevent a crash – at higher speeds it will reduce the severity.
Adaptive Cruise Control (ACC) tracks the vehicle in front, and automatically maintains a desired minimum distance (or time headway) from that vehicle. So long as this minimum distance is maintained, the vehicle will travel at the set speed. If the separation distance falls below this minimum value, the ACC system adjusts the vehicle’s speed to regain the minimum headway (in time or distance).
These systems detect slow moving or stationary objects and pedestrians that are in the path of a vehicle that is reversing – and warn the driver accordingly. Detecting these objects requires the use of relatively short-range sensors on-board the vehicles, such as a rear-view camera. Examples of these systems can be found fitted to many of today’s vehicle models.
Lane departure systems aim to help drivers avoid accidents that could result when a vehicle leaves its own travel lane and strays into the path of a vehicle in another lane. This is achieved by warning drivers and/or assuming temporary control of an at-risk vehicle. Among the most well-known of these systems are:
ITS technology has been tested in applications that will avoid, or to decrease the severity of, collisions at intersections. These systems track the position and status of vehicles within a defined area on approach to an intersection through the use of vehicle-to-vehicle communications and/or vehicle-to-infrastructure communications. If a potentially dangerous situation is detected that is likely to lead to a collision warning messages are delivered to the driver – for example, in cases where a vehicle fails to stop at a red light or attempts to make a turning manoeuvre in the absence of an adequate gap.
ITS applications have been developed to help eliminate and/or reduce the severity of accidents that result from poor visibility – such as night driving, heavy rain or foggy conditions. These systems include in-vehicle sensors that can capture images of the driving environment and display them graphically to the driver, for example through a head-up display. One example that illustrates the concept is the Driver Assistance System for Snowploughs developed by the University of Minnesota http://www.lrrb.org/media/reports/200313.pdf).
The goal of safety readiness ITS applications is to eliminate and/or reduce the number of collisions caused by impaired drivers (though tiredness, alcohol or drugs), a failure of vehicles’ components, or any degraded infrastructure conditions that could affect the safety of the vehicle. Systems are available that monitor the performance of the driver – and either warn or assume temporary control of the vehicle if a driver’s performance is impaired. Other systems monitor the performance of critical components of a vehicle (such as the braking system), and warn drivers of their imminent failure. There are also systems that can monitor the roadway and provide warnings to the driver of unsafe conditions – such as loss of tire traction on wet or icy road surfaces. (See Policing/Enforcement and Warning Systems)
Pre-crash restraint ITS applications anticipate an imminent collision and activate the appropriate passenger safety systems prior to the actual impact. For example, sensors are available to detect the rapid closing of distance between the vehicle and an obstacle. On detection, the system attempts to reduce the danger of the impact of the collision by settings restraints to absorb or dissipate the force of the impact – such as triggering an airbag. (See Partially Automated Driving)
A long-term goal of vehicle safety systems is a fully automated highway-vehicle system (AHVS) – where specially equipped vehicles travel, under fully automated control, along dedicated highway lanes – or where a self-driving vehicle pilots itself through mixed traffic. The AHVS concept has the potential to significantly improve the safety, as well as the efficiency, of highway travel by reducing the number and severity of crashes, decreasing congestion, and reducing vehicle emissions and fuel consumption. (See Automated Highways and New Applications)
The safety risks associated with AHVS operations need to be analysed carefully so that the risk of mal-function is minimised. Many automotive manufacturers are currently involved in significant research and demonstration projects aimed at making autonomous (or self-driving) cars, a reality. A number of countries are preparing to test the readiness of driverless cars. Nissan, for example, has promised the production of autonomous cars by 2020 – and Google has sponsored the development of a self-driving car. Initiatives from public and private enterprises may help accelerate the deployment of self-driving cars. An example is here: http://www.autoblog.com/2013/08/27/nissan-promising-autonomous-car-production-by-2020/ (See Warning & Control)
ITS has a lot to offer in terms of supporting and facilitating the maintenance and management of highway infrastructure, winter maintenance operations, as well as improving the management and safety of road construction and work zones. Technology applications range from those aimed at tracking and routing support for maintenance and construction vehicles, to systems designed for monitoring and predicting weather conditions, to applications aimed at construction and work zone management. Some examples include:
ITS technologies can be used to keep track of maintenance and construction vehicles such as snow ploughs – so that operators can monitor whether required tasks are being carried out as planned. ITS can also be used to monitor the condition of maintenance and construction vehicles – using on-board sensors to alert users of any required maintenance or repair activities. (See On-board Monitoring and Telematics)
Using Road Weather Information Stations (RWIS) and other similar environmental sensors (whether fixed location or on-board maintenance vehicles), ITS can help collect accurate, localised information about the weather – including road surface conditions. ITS can also help in the processing of the data and in disseminating information to the public. Information from RWIS can help detect hazardous conditions – such as icy roads, high winds, dense fog – and to plan, more effectively, winter maintenance operations and optimise resource allocations. (See Weather Monitoring)
Winter maintenance operations can be supported by systems that monitor and track routes for snow ploughs and grit spreaders – to determine the correct roadway treatment needed. This will be based on current and predicted weather information and information collected from environmental sensors. (See Weatther Management)
ITS can play a key role in helping improve the safety of work zones and construction sites on highways – as well as better manage the flow of traffic through the work zone. Information collected from permanent and temporary ITS monitoring facilities can be used to better control traffic and to provide advisory and warning messages to drivers – for example through dynamic message signs (DMS). The traffic information collected from the work zone can also be shared with traffic operations centres and to support traveller information systems. (See Work Zones)
ITS technologies can be used to monitor the condition of critical infrastructure such as bridges and road tunnels. Information from fixed sensors as well as vehicle-based sensors play a part. One recent idea is to use information from probe vehicles – about their vertical acceleration – to determine the pavement surface condition and detect different types of distress, such as potholes or surface roughness. (See Probe Vehicle Measurements)
ITS is not only about the use of telecommunications and information processing in road transport operations. Many of the challenges that accompany the introduction of ITS are not about technology but about different ways of working – especially different organisations working together in new ways. There is now a large body of ITS ‘know-how’ that draws on the practical experience of substantial numbers of ITS projects and case studies.
To properly understand how ITS works, there are a number of issues to take into account:
For ITS to work, a number of technologies are needed.
Collecting accurate information about the status of the transport system is a pre-requisite for almost all ITS applications. The problem needs to be identified before coming up with a solution. The front-line group of enabling technologies are those used for collecting real-time traffic information. Some of these are infrastructure-based and others are vehicle-based.
Infrastructure-based detection technologies include:
Vehicle-based detection technologies include:
(See Data and Information)
Telecommunications may be compared with the nervous system in the human body. Communication networks link the different components of an ITS system together, allowing for the exchange of information and for the implementation of the different traffic management and control strategies. They also link the traveller to the system allowing for the dissemination of useful information. (See Telecommunications)
To be useful, the real-time traffic and environmental data collected from the field must be processed, fused together with different sources and analysed. Data processing and computing technologies refer to the set of computer hardware and software that is needed to make sense out of the data, and convert the data into information that can support decision-making. (See Basic Info-structure)
Effective communication with travellers is an essential component of several, if not all, ITS applications. ITS uses several traffic information dissemination devices to keep travellers informed about current as well as expected travel conditions. These devices include Dynamic Message Signs (DMS), highway advisory radio (HAR), cable TV, traveller information websites, social media (Facebook, Twitter) and the internet, dedicated phone systems, and in-vehicle display devices. (See User Interfaces)
The most common technology currently used for location and navigation are satellite navigation systems for location determination (latitude, longitude, and elevation). These triangulate ground position based on satellites signals – and are known as Global Navigation and Satellite Systems (GNSS). The most well-known is the USA’s military Global Positioning System (GPS). The European Union is developing a compatible civilian system, GALILEO – aimed at providing higher availability and improved positioning accuracy. (See Navigation and Positioning)
Light Detection and Ranging (LIDAR), a remote sensing technology, can be used to generate three-dimensional information about different locations and their surface characteristics. LIDAR, either airborne, mobile or terrestrial, has been used in transport for various tasks, such as surveying, highway design and highway safety. With accurate mapping and positioning of roadway infrastructure, LIDAR can support various ITS applications – such as real-time roadway-weather monitoring and real-time evacuation support during emergencies.
Control technologies constitute another group of enabling technologies for ITS applications. They can be divided into two broad categories:
One of the most widely deployed ITS applications is in the area of electronic payment, which:
In terms of hardware, the most common technologies for electronic payment are: smart cards, transponders (such as a toll tag) and more recently, smart phones. (See Electronic Payment)
This group of ITS enabling technologies includes those designed to support Archived Data Management Systems (ADMS) – or what are sometimes also known as ITS Data Warehouses. ADMS offers an opportunity to take full advantage of the data collected by ITS devices in improving transport operations, planning and decision-making – often at a minimal additional cost. The technologies supporting ADMS are designed to archive, bring together (or fuse), organise and analyse ITS data from different sources and can support a wide range of useful ‘intelligent’ applications. (See Data Management and Archiving)
A feature of integrated systems that are designed to serve the mobility needs of people and goods distributed spatially over a large geographic area, almost always requires the collaboration of several stakeholders. (See Stakeholders)
Any ITS deployment generally involves a range of organisations. It is often the case that a champion or client agency will take the lead. This could be a road authority or a department of transport, local government , a public transport operations agency – or a coalition representing all these parties. (See Inter-agency Working)
One method of ITS procurement will involve a specialist consulting firm acquiring a wide range of ITS equipment and technologies from a number of vendors and manufacturers of ITS technologies. The consulting firm would typically act as a system integrator bringing together all the technologies and components so they work as a truly integrated system. (See Managing ITS Implementation)
For ITS to be effective, its different components have to work together as one integrated system. The components have to be able to communicate with one another, and need shared data dictionaries and communications protocols. This underscores the importance of adopting a systems engineering approach to the design, deployment and management of ITS projects. (See Systems Engineering)
A systems approach will consider the context of ITS deployment and how all the component systems fits together. A fundamental aspect of the approach is that User Requirements are defined at the start – and taken into account in the design and development of the system. It is different to a technology led approach. It also explores the various system interfaces, the data that needs to be exchanged, the equipment and communication standards – and the building blocks that need to be in place for effective operations. A systems approach also considers how ITS would fit within the larger regional transport system, and investigates how to maximise the benefits from the system. The approach considers not just the technical challenges, but the institutional ones as well – which are key to integration and collaboration. (See ITS Architecture)
Human factors are of great importance to ITS deployment and effectiveness – from the perspective of infrastructure, operations and vehicles. For vehicles, it is important to ensure that ITS applications do not distract drivers from their primary driving task – or overload them with information. This is particularly the case with Advanced Driver Assistance Systems (ADAS) – which continue to mature and increase in sophistication. Another important area is smart phone usage and “infotainment” applications. Many studies have shown the dangers of using a phone while driving (and worse still – texting while driving), and many countries have issued laws banning the use of cell phones and similar devices whilst driving.
The likely response of drivers and travellers to an ITS system recommendation is another key area. An ITS system may recommend to drivers, a certain speed or a specific route to arrive at their destination – but there is no guarantee that the driver will follow the system’s recommendation. Building trust in ITS systems is critical for public acceptance.
In terms of future development of ADAS, human-machine interaction is critical in ensuring that the driver interacts safely with the vehicle and the technology on board. The prospect of vehicles with various levels of automation – which may soon lead to partially or fully autonomous (self-driving) vehicles – makes this a more urgent issue. (See Human Factors)
ITS is all about acquiring data and information, the exchange of information, the processing of information, the use of information to support decisions – and the dissemination of information to travellers and other end-users.
It shows ITS using detection and monitoring technologies to collect data in real-time – about the transport system and other external factors (such as the weather). The ITS then uses its communication network to exchange this information between different traffic centres, different agencies, and different regions. The information gathered is then processed and analysed to understand how the transport system is operating – and to identify “optimal” management and control strategies aimed at improving system performance. The information is also disseminated to a wide range of ITS stakeholders – such as traveller information to the transport system users. (See Data and Information)
ITS applications include the information infrastructure that supports the collection, archiving, processing and distribution of a wide variety of data – for example about travel demand, traffic volumes and journey patterns.
Data is collected continuously by different ITS tools with different characteristics – such as quantity, frequency, timing (real-time, near real-time or historical), and reliability. By systematically validating, storing, archiving and fusing data from different sources, the compiled data can be mined and analysed to gain useful insights into how to best plan, operate and manage the transport system.
ITS data provides a very important resource for calculating performance measures to assess the quality of service provided by the road network – and any associated ITS applications, such as automatic incident detection.
Performance measurement is a topic that has received increased attention in recent years. Growth in the data sources for ITS – such as social media, GPS and communication-enabled connected vehicles – are coupled with changing security and privacy concerns. The impact on the planning, design and evaluation of ITS information infrastructure will be in the forefront of any ITS deployment consideration. (See Performance Measures)
The development, deployment and operation of ITS requires coordination and collaboration among a wide range of stakeholders. (See Stakeholders) Those stakeholders typically include (amongst many others):
The deployment of ITS also needs a “champion” – or a strong leader – who believes in the vision and can inspire others. The first step in any ITS planning initiative is to identify the key stakeholders and build local partnerships (with memoranda of understanding if required) to allow for combined action and joint problem-solving. (See Inter-agency Working)
In ITS the term ‘architecture’ describes a structured framework within which the components of ITS systems are brought together so that the whole can function efficiently – much as construction products and services in a building.
ITS architecture is essential for the planning and design of an ITS deployment – that will meet the needs and requirements of users. An understanding of ITS architecture helps to define how the component systems need to interact with each other – and will clarify the roles of individual stakeholders in the implementation process. The analysis should be firmly based on an assessment of the functions and system performance that are necessary to meet user needs. (See What is ITS Architecture?)
An ITS architecture can provide many benefits to a region as it begins to develop and deploy ITS-based systems and services. A properly designed ITS architecture will:
The concept of interoperability is very important in ITS. For example:
To facilitate this kind of interoperability, an ITS architecture (where one has been adopted) will identify the system interfaces or information flows that need to be harmonised – and, if possible, standardised. The ITS architecture is an important tool for the success of this process, since it describes how the different components of a system should interact with one another. (See ITS Architecture)
The real advantage of interoperability becomes more obvious when the different ITS systems share and exchange data and information with each other. For example:
The process of linking the different components of a system is typically referred to as “system integration.” This becomes a major issue as more and more ITS components are deployed. (See Systems Engineering)
Within the context of ITS, the term “user services” is used to describe what ITS does for the users of the transport system – including travellers, transport operators, planning organisations, road authorities, government ministries and departments of transport. The US National Architecture, for example, currently defines 33 ITS user services, grouped into eight major user services bundles as shown here: http://www.iteris.com/itsarch/html/user/userserv.htm.
ITS user services share a number of basic characteristics.
In the US National Architecture, the different user services have been arranged or grouped into eight bundles, which define focus areas for ITS applications: (See Using the US Architecture)
The European Frame architecture adopts a comparable approach based on user needs that are grouped into nine broad areas:
The Frame Architecture also provides for links to other modes of transport – for example, to provide travellers with multi-modal travel information, to manage mixed mode at-grade crossings (where a road or highway meet at a level crossing) and to respond to incidents that take place on other modes. (See. Using the FRAME Architecture)
Evaluation studies and operational tests have shown that ITS applications have provided significant benefits across surface transport modes. In the road transport sector, ITS aims to improve the performance of roads and highways by using real-time and historic information on the status of roads and traffic. ITS applications can enable better road transport operations – more safely, efficiently and in a more sustainable way, with better inter-modal connections. Benefits include safety, journey time, travel reliability, energy consumption, emissions and customer satisfaction. (See Benefits of ITS)
ITS includes diverse stakeholders in terms of disciplines, business areas and ownership:
Traditionally, the public sector has been responsible for the operation and maintenance of roads and highway infrastructure. Public agencies, such as a road or highway authority or a public works department, have had primary responsibility for the planning, design, operations and maintenance. For example, public agencies are usually responsible for ITS enabled services – such as incident management and traffic signal operations.
Similarly, the public sector has, in the past, taken full responsibility for the planning, design, investment, operations and maintenance of the dedicated ITS infrastructure (which includes management centres, field devices and communication infrastructure). Increasingly much is being out-sourced to the private sector under service contracts. Nevertheless the public sector continues to take the lead in long term planning for traffic and highway ITS infrastructure. (See Dimensions of ITS Deployment)
Experience shows that ITS involves an increasing number of organisations – as the full potential of new technology is realised. The table below illustrates this with examples of the more common objectives for investing in ITS – showing the varying degrees of complexity and stakeholder groups. Senior officials of public agencies and chief executives of private sector companies will often have a close involvement because of the level of commitment required.
Strategic Objective | Stakeholder Groups | Candidate ITS Applications |
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Improved urban traffic management |
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Introduction of new automatic payment systems or access controls | Many of the above, plus:
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Strategic and tactical management of inter-urban traffic | Many of the above, plus:
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Better integration of transport modes | Many of the above plus:
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Added-value services for private motorists and vehicle fleet operators |
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Stakeholders can be categorised into primary and secondary stakeholders. Primary stakeholders are distinguished by the level and nature of their involvement:
For example, in deliveries and commercial vehicle operations, the vehicle owners and delivery services providers and their customers are the primary stakeholders for ITS services to customers. Enforcement bodies such as the police and vehicle examiners are primary stakeholders in relation to weights and permits regulations and enforcement. From the public policy perspective local communities will also have an interest, albeit a secondary one unless there is public concern about the potential impact of operations.
Both primary and secondary stakeholders have roles in the planning, development, operations and maintenance of ITS projects. All stakeholders with a potential interest in the project must be identified and engaged – from planning to operations and maintenance stage of a project. Their input and participation is necessary for the successful realisation of an ITS project.
It is important to be aware of, and sensitive to, possible issues at all times – in what may be an evolving situation, as an ITS project develops. Secondary stakeholders can introduce issues which must be recognised and dealt with. Generally it is better to uncover interests and issues early on in the planning stages – so that proper adjustments can be made. An effective communication strategy with stakeholders provides the opportunity to develop contingency options.
ITS investments usually need political and public support. Public agencies must communicate the anticipated benefits of the ITS deployment in terms that policy makers and the public can understand. In the early stages of ITS deployment, a careful assessment of risk is essential covering the technology, market perspective, political and public acceptability. Some aspects may require a regulatory framework to ensure public safety, interoperability and rules for procurement – and where necessary an enforcement policy (such as speed control.) (See Contracts)
A priority for ITS is to consult the widest possible range of interests and to build local partnerships to achieve consensus on objectives and scope of investments in ITS – and joint problem-solving. Stakeholders are impacted by any failure or success of an ITS project. This means there is a need to develop an all-inclusive process to identify and engage all stakeholders from the start of the planning phase of ITS projects. This may lead to the involvement of new stakeholders, such as financial institutions, retailers, broadcasters, telecommunications providers and value-added service providers. Each stakeholder will have their own distinct business practices and goals – and should take ownership of their roles and responsibilities in any ITS project at each stage of the project.
There is often a role for an ‘ITS champion’ to take the initiative, drive forward consultation and keep all partners and stakeholders on board.
A total system approach to ITS deployment means paying attention to both technical concepts and institutional measures needed to integrate key technologies to deliver effective user services.
Successful ITS operations are enabled by a regulatory and institutional framework that is fit for purpose – with cooperative agreements between stakeholders that define clearly each party’s role and responsibilities. An equitable cooperative agreement between stakeholders – guided by suitable risk distribution, cost sharing and revenue or benefit sharing – may solve some of the regulatory and institutional challenges. (See Interagency Working)
A self-contained ‘silo’ mentality within an organisation may frustrate the development of ITS services. A lack of attention to end-user needs and requirements and poor management and project control in a primary stakeholder organisation – may also undermine the planned ITS deployment and incur excessive cost. Deficiencies such as these, may make the ITS service economically unfeasible.
A cooperative agreement can take the form of a ‘Concept of Operations’ – where each stakeholder’s roles and responsibilities are described and each party agrees on the allocation of operational roles and responsibilities.
The agreement should be based on appropriate risk distribution, cost sharing and revenue or benefit sharing – according to the role and level of involvement of each stakeholder. This must be developed at the planning stage of an ITS project and may have an important place in defining any ITS architecture. (See How to Create and ITS Architecture?)
By way of example, the table below summarises a Concept of Operations that was developed for Bloomington/Monroe County in Indiana USA, as a part of the county’s regional ITS architecture. Stakeholders are mapped to different transport services and each stakeholder’s roles and responsibilities are specified.
Transport Service | Stakeholder | Role/Responsibility |
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Emergency Management | Public Safety Agencies |
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Freeway (Motorway) Management | Highway Operator |
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Incident Management | Highway Operator |
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Public Safety Agencies |
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Maintenance and Construction Management | Highway Operator |
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City/County Authority |
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Highway Pavement Management | Highway Operator |
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Surface Street Management | City/County Authority |
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Public Transport Management | Bus/ Coach Operators |
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Traveller Information | Highway Operator |
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The leading stakeholders in an ITS deployment may parallel those involved in a construction project: the client, professional consultants, products and service suppliers, contractors and specialist subcontractors:
Transport professionals who are responsible for launching ITS at project or programme level, may be unfamiliar with certain aspects of a deployment – either technical or institutional. (See ITS Technologies and Strategic Planning)
ITS covers a wide range of systems and services. Different players are involved – so stakeholder roles and attitudes and the legal and institutional issues vary for each sector. There will be wide variations between different applications and individual institutions, but there are three broad groups of stakeholders that invest in ITS:
These three groups adopt very different evaluation systems when they consider whether to invest and allocate their budgets to ITS deployments:
The interactions between these very different requirements is illustrated below. For ITS projects to be viable, they will often require justification against at least two, if not all three of the underlying value criteria. Failure to meet one or other of the investment tests will produce a classic “chicken and egg situation” – who goes first, the supplier or the purchaser in making a commitment to the system or product?
Inter-dependencies between the public sector, the private sector and consumers (© World Road Association)
Private sector involvement is generally motivated by the opportunity to generate revenue and/or make a profit. Commercial businesses must be able to generate a profit through their activities to survive in a competitive market place. The continuing development of technology and advances in user needs and expectations means that the potential for new products and services is always there. The private sector can provide these new products and services, as and when time demands. Increasingly, the public sector is looking to the private sector, for the investment in ITS infrastructure and the delivery of certain ITS services – such as providing travel data. The private sector business case will largely depend on risk assessment of several factors. (See Formulating a Programme)
It is likely that the private sector will wish to develop market opportunities for new service needs arising from public sector investments in ITS. For example, a company might make use of traffic data (advisory and predictive) collected by public agencies to develop customised, real time travel information as a value added service for its customers. Arrangements of this kind – if they are exclusive to one provider – can become problematic unless they have been awarded on the basis of fair and open competition.
Private investment in road infrastructure and traffic services is growing as many public agencies struggle to meet increased travel demand within limited budgets. For example, toll roads and traffic control centres are often implemented through a partnership contract or franchise (See Contracts and Toll Collection). Private sector participation offers new opportunities and challenges to the transport industry.
The challenge in a public private partnership lies in how to achieve a balance between the policies and objectives of public agencies – while satisfying the business goals of private companies. To achieve a successful public private partnership, various issues need to be addressed:
In preparation for negotiations with private industry, public agencies need to determine their requirements – which may be encapsulated in an ITS regional architecture. By defining requirements before entering into a resource sharing agreement the stakeholders will be in a stronger position to conduct the negotiations.
Motivating factors for public private partnerships in ITS include:
Examples of viable partnerships which benefit both sectors include:
ERTICO – ITS Europe represents the interests and expertise of around 100 public and private partners involved in providing Intelligent Transport Systems (ITS) services. It facilitates the safe, secure, clean, efficient and comfortable mobility of people and goods in Europe and beyond through activities supporting the development and deployment of ITS.
Specifically, ERTICO:
ERTICO’s public private partners include mobile network operators, public authorities, academic and research institutions, service providers, suppliers, traffic and transport industry, users and vehicle manufacturers.
Source: http://www.ertico.com/assets/Partners-List/Partner-listJune-142013.pdf
ITS works when the supporting infrastructure – which includes roads, ITS devices, vehicles, terminals, management centres – communicate with each other and with users. For a road authority, the ITS infrastructure components can be divided into four different categories: field, centre, vehicle and telecommunications.
The diagram below shows how field, centre and vehicle infrastructures connect to each other. Centres may communicate with each other and with field devices through wired or wireless technology. Vehicles communicate with centres and field devices through wireless infrastructure.
Figure 1: ITS Infrastructure Components
ITS Architecture plays an important part in Road Network Operations. The ITS architecture is a primary element in ITS planning. Two types of ITS architecture are typically defined:
A high level ITS architecture provides the framework for the deployment of ITS across a wide geographical area with multiple jurisdictions and different stakeholders participating in common or inter-dependant operations. The architecture specifies how the various ITS components interact with each other to address the transport problems. It provides the basis for planning, designing, deploying, maintaining and integrating systems to realise transport objectives.
An ITS architecture does not specify the ITS scheme design in detail. Nor does it require a particular design approach. Instead it does the important job of specifying the performance criteria that the system components must satisfy – and defines a general framework from which several alternative designs or design options may be developed. These distinct designs will conform to the common ITS architecture. (See What is ITS Architecture?)
An ITS architecture should define the following:
Maximum benefit from ITS requires interoperability and interchangeability of systems between regions and within a region. Interoperability refers to the condition where different types of systems can interface with each other to meet the system’s functional requirements. Multiple brands of a device on the same communications channel is an example of interchangeability. One of the primary goals of ITS is to integrate a variety of previously independent systems to minimize redundancy and maximize efficiency – so adhering to ITS and other industry standards will satisfy the interoperability and interchangeability requirements and support future efficient system expansion. Legislative requirements to comply with industry and ITS standards in any ITS project will support interoperability, interchangeability and future cost-effective expandability of the system. (See ITS Standards)
Technology is changing at a rapid pace and this trend is expected to continue indefinitely. ITS builds on technology-based services – and the pace of technological change is an important consideration in planning and deployment. Three issues must be addressed when considering changes in technology for any ITS applications. These are: upgrade, legacy systems and systems integration.
With technology changing rapidly, even during the course of an ITS project, it is important to anticipate the possibility of system upgrades. Newer technologies can improve the performance of an already deployed system – and may require a decision on whether to upgrade the system or replace it. Where it is possible to look ahead, work planning and design should allow for the possibility of upgrades so they can be accommodated efficiently and without technical complexity. A possible disadvantage is that system upgrades may require highly skilled professionals to operate and manage the new systems in the future.
As new systems and upgrades come on line, they must be integrated with earlier “legacy” systems. The challenge lies in making the new systems interoperable. ITS architecture can show where and how established legacy systems will need to interface with new systems to deliver the desired (integrated) system functionalities and performance. A field evaluation plan for testing the interoperability between a legacy system and new systems will provide the basis for testing the integrated system after deployment.
Systems integration is about how different systems are connected together so that they can perform the desired tasks in an optimal way. ITS requires different types of hardware and software (which may come from different manufacturers and be implemented at different times) to be integrated to satisfy user requirements.
Problems – that can pose a significant challenge to systems integration – technically and because of the cost, are:
Adhering to established industry and ITS standards and the use of open architecture will support future cost-effective systems integration.
A system-wide outlook at the inception of a project will help develop a deployment plan that supports a cost-effective implementation strategy:
If the design provides for interchangeability of components it will encourage competition and allow scope for future improvements in cost, design, functionality and safety (See ITS Architecture):
ITS architecture can show where standard interfaces will bring significant benefits:
ITS architecture shows how different stakeholders are connected with one another through data exchange:
The existence of an ITS architecture can assist in integrating systems coming on-line in different phases:
ITS architecture can support security services related to disaster response and evacuation, freight and commercial vehicles, hazardous materials, rail, transit and transport infrastructure:
Bloomington/Monroe County USA, Regional Intelligent Transportation Systems Architecture, 2008.
Chowdhury, M. and Sadek, A., Fundamentals on Intelligent Transportation Systems Planning, Artech House, Boston, MA, 2003.
Fries, Chowdhury and Brummond, Transportation Infrastructure Security Utilizing ITS, John Wiley & Sons, 2008.
U.S. Department of Transportation, National ITS Architecture, www.iteris.com/itsarch (accessed on December 1, 2013).
Road Network Operations are part of a much wider activity known as “transport operations” – which comprise the methods and techniques used to support the movement of people and goods and maintain optimal conditions on a transport network. In general, this is achieved by measures that are designed to match transport supply – the capacity of the transport system – with transport demand. When transport demand exceeds the available capacity, the result is congestion.
Video: Economics of Land Transport in Singapore - Managing Traffic Congestion in Singapore
Transport operations have many objectives including:
The objectives of “transport operations” are well-aligned with those of Intelligent Transport Systems (ITS) – and as a result, ITS has a lot to offer in terms of improving transport operations. The connection between ITS and transport operations is illustrated by the following three aspects of transport operations:
The major functions of ITS-related road network operations are:
Road network monitoring and safety – involves all measurement, resources and procedures aimed at comprehensive management along the overall road network. It is also focuses on road conditions and data collections in order to promptly react to events occurring in a specific place on the network. ITS services can make transport safer and more secure, maximising capability to contain and reduce the impact of disasters.
Road network providers and operators put in place a series of procedures and operations for the management of incidents and events, to re-establish normal conditions. This includes emergency management, winter services management and management of maintenance activities.
Road administrations are responsible for monitoring and controlling their road network. Management of traffic flows is a critical factor that influences the management of the overall network – and road users’ expectations. Besides taking action when traffic appears to be very congested, road network operators also need to plan and forecast traffic flows – considering different analysis scenario and solutions, in order to provide road users with tangible improvements to their journey.
The publishing and distribution of information to road users on road network conditions and traffic flows, represent the interface between road operators/road administrations and public users. Data available to users tends to influence their behaviour on the network – and this needs to be taken into account as an important instrument to convey traffic flows. Information published can be: real-time or future-forecast.
ITS technologies lie behind good traffic management and information delivery for both urban networks and interurban roads. Pro-active and re-active measures can be applied. Pro-active measures focus on the prevention of incidents/congestion. Re-active measures focus on the detection/verification of incidents and unsafe road conditions, response and clearance, and recovery to normal operations. Other solutions include better road works planning, lane restrictions, bad weather and road conditions alerts, and automatic braking systems.
Many ITS applications can help support road network operations. Examples include:
The goal of public transport operations is to help increase and retain ridership, cut down on the cost of operations (principally fuel and staff costs), and improve the level of service for passengers (See Passenger Transport).
Examples include:
Optimising freight operations and the movement and distribution of goods is a central part of transport operations that is vital to a nation’s economy. The effective operation of road networks directly benefits freight operations. Roads that are well-managed enable timely deliveries and reduce vehicle turnaround times and costs to freight operators. This has becoming more important with the spread of internet retailing and just-in-time stock management procedures. Freight operators may face additional challenges from local government policies – introduced to control heavy vehicle movements in urban centres.
ITS can contribute to improved efficiency and security of freight operations:
ITS can also help freight operators in other important ways – by identifying available parking and ensuring compliance with driving time and rest period regulations. The absence of available parking and of ways to identify it in good time, can create safety hazards – with truck drivers being obliged to park on roadsides or highway access ramps.
ITS and Freight Operations in USA and Europe
In the US, advanced routeing and decision-making software – and organisation for the routeing of time-sensitive deliveries – has increased deliveries per driver hour by 24%.
A smartphone app developed for European truck drivers enables them to look up available parking options across borders – with details of security and comfort provision – and to share the information with their schedulers, who can then plan future routeings more efficiently (See Freight and Commercial Services)
People and businesses want transport that is safe, cost-effective, reliable, convenient and respectful of their environment. ITS (Intelligent transport systems) can save time, money and lives and protects public health, townscapes and landscapes – if they are properly planned and implemented with those benefits in mind. It does this through the application of information processing and communication processing technologies to road transport – car, truck, bus, tram, metro – and the road/rail transport infrastructure.
Transport and travel are essentials for everyday living, working, commuting, learning, shopping, leisure and, for companies, trading and distribution of goods. Virtually every person in the world, and every organisation, is a transport user or dependent in some way on transport. This is true whether people are homebound or based at static locations, or whether they are physically on the move on the roads - car drivers, truck and delivery operators, public transport vehicle drivers and passengers, cyclists or pedestrians. They all want smooth, safe and convenient journeys.
As economies, populations, migration, commerce and consumer demand grow, so does the pressure on transport infrastructure and systems, from its users and others who depend on it. This has become increasingly evident over the last few decades, with increasing road congestion and overcrowding on public transport. The emphasis is now on ensuring that users benefit from reliable and resilient transport. The solution lies in technology – specifically ITS – working in a policy context.
The central feature of ITS is its ability to deliver in real-time, traffic and travel information and a flexible means of network control. It is a key enabler of sustainable transport system which:
The way that ITS operates is often invisible (buried cabling or wireless communications). While people may experience some form of ITS every day (for example, traffic signals or variable message signs on roads, or searching for travel information on websites or via their smartphones), most will not realise how widespread ITS is in their daily lives. Nor will they appreciate how much they can benefit from the ways in which it makes their transport more user friendly.
ITS practitioners (including road network operators, managers, planners, engineers and surveyors) need to understanding the benefits of ITS and being be able to argue convincingly for investment in these technologies – often to a non-technical audiences such as governments, the media and local communities. This highlights the importance of gathering firm evidence of benefits through monitoring and evaluation of the outcomes of ITS deployments – and using the results in the appraisal of new projects. (See Project Appraisal)
More and more ITS schemes have been, or are being, evaluated, resulting in an extensive and growing literature on costs and benefits, including how to assess them – and understanding exactly what the benefits are and who experience them. See Evaluation. Informed awareness of ITS can be a critical factor in decision making by national, regional and local governments, directors of transport operating and related companies, investors and developers looking for locations for expansion, and the management and financial consultants advising public- and private-sector clients.
Its membership is open, with the aim of bringing together, and meeting the needs of, not only ITS professionals, but also transport planners, researchers, manufacturers and suppliers of ITS systems, decision-makers in public- and private-sector client organisations, as well as the transport-using public. This last is a very important audience, whose needs for ITS information are not always well catered for.
Members have access to its website library and information services.
The cost of physically extending existing infrastructure – particularly in built-up areas – needs to be assessed against competing demands for transport investment and other priorities. Decision makers also need to be confident of being able to manage new roads efficiently to gain the optimum benefits from them. This can be achieved by planning to install ITS technologies at the outset of a new construction. (See Deployment Strategies)
To a large extent developing economies can draw on the experience of the developed world in obtaining the benefits of proven systems without having had to bear the full costs of bringing them to market. This may also provide an opportunity to create employment through commercial partnerships between local businesses and foreign suppliers. Care needs to be taken to ensure that any ITS deployment is well adapted to the local context to ensure success and maximise benefit. For example, direct transfer of ITS technology rarely works without some modification to take account of technical and maintenance skills levels and other factors – such as the environmental and cultural context, public readiness and acceptability. Poor road and vehicle maintenance, and poor driving skills, lead to high levels of road traffic accidents – nearly three quarters of all those in the world.
Developing and emerging economies have a large proportion of vulnerable road users (VRUs) – for example, pedestrians, cyclists, hand-carts, cycle-rickshaws and animal transport. According to the Indian Ministry of Road Transport and Highways, over 18% of all road traffic accident deaths involve vulnerable road users. The challenge is to make ITS technologies and applications that are flexible enough to respond to this traffic mix.
Most important is the early development of a policy and technical framework for ITS deployment in a local context. This will set out in advance the principles for specifying and choosing individual ITS products and services that meet transport needs as efficiently as possible. It will also consider the institutional capacity to work across organisations to install and maintain advanced technology – to secure maximum benefit to the economy and long-term gains in efficiency. (See Deployment Strategies)
ITS deployment in road network operations helps to provide users with better managed urban and interurban roads. Congestion is a huge source of delay and unreliability in travel times and journeys. Its cost is high – and though this impacts directly on those using the roads, it also impacts on the general public in terms of increased transportation costs for personal mobility and the price of goods.
US research indicates that traffic congestion-related emissions in a single year are valued at approximately $31 billion, with an additional $60 billion related costs in wasted time and fuel. A major share of the costs of USA truck congestion ($23 billion in 2010) was passed on to consumers in the form of higher prices of goods and services. Developing and emerging economies are particularly susceptible to congestion – with queues often many kilometres in length. It is estimated that the Philippines is losing ₱2.4 billion (pesos) a day in potential income due to traffic congestion.
Road network monitoring plays a critical role in collecting data on route condition and performance information. The quality of the data derived from ITS applications is key in enabling transport planners to analyse the problems of congestion in detail and develop specific solutions based on experiences of travellers and freight operators. ITS products and services which make use of data to provide:
ITS benefits different groups of users:
Everyone benefits from ITS applications that:
Some advantages of ITS come at a perceived cost to the user. There can be a trade-off. The underlying issues for an individual – and for society as a whole – are “is it worth it” and “do I get value for money”? For example:
A particular local issue for public transport users is the last 1km-2km stage of their journey – between the last stop and their final destination (home, workplace, shops or leisure activities). Journey planners can help by factoring in:
For rural public transport users, dependent largely on buses, the basic communications infrastructure needed to give them urban-style real-time passenger information is typically lacking. This is because of the lack of incentives for operators to install these for relatively small numbers of passengers – and the high cost of installing displays at remote bus stops.
Potential solutions include crowdsourcing, with smartphone-equipped passengers acting as both providers and consumers of travel information via a website. Their satellite positioning-enabled devices can be used to upload information on the bus on which they are travelling for the benefit of others.
Disabled drivers need reliable information on the availability of appropriate accessible parking places near to their planned destination. New travel applications are being developed for smartphones which use GPS locational technology, parking space sensors and two-way messaging to enable disabled drivers on the move to find and pay for disabled parking. An example is the City of Westminster’s free “ParkRight” application (See https://www.westminster.gov.uk/park) which provides real-time information on over 3,000 parking bays in London’s West End. It can filter bays for disabled parking, provide information on operating hours and tariffs, interact with vehicle satellite navigation systems, and allow users to pay for and manage their parking sessions.
Public transport users with mobility difficulties, need to be able to board and travel on public transport safely and comfortably – and they need access to travel information in a suitable format, so they can plan their journeys in advance. This includes information about interchanges and transport terminals (including the availability of elevators) and arrival times of buses, trams and trains – for transport services offering suitable access for their specific mobility needs. For example, passengers in wheelchairs need up-to-date information about any impediments to their planned journeys. Accessibility information is provided on many websites for travel planning purposes covering accessible drop-off points, parking, entrances and step free access to stations. In Paris, information on metro stations where elevators are out of action can be accessed before travel. Similarly in the UK, the National Rail Enquiries’ “Station Made Easy” service provides accessibility information for all stations (See http://www.nationalrail.co.uk/stations/sjp/BHM/stationAccessibility.xhtml)
Passengers with mobility problems can be encouraged to make greater use public transport by the introduction of technology. For instance:
SNAPI (See http://www.snapi.org.uk/) has produced a European standard for coding user needs to enable adaptable user interfaces on a range of self-service terminals (such as ticket machines) and automatic gates. The user’s needs are coded onto a contactless smartcard which can be pre-set to request:
The SNAPI reader is connected via a USB cable to a user’s PC (onto which the relevant software has been preloaded) or built into at-station machines. Displays revert to normal on withdrawal of the SNAPI card.
Operators investing in these ITS products benefit – the improved accessibility they offer is good for business, attracting passengers who would not otherwise think of using public transport.
ITS applications impact on the local communities within which they are deployed. Cars, trucks, buses and trains all affect the people living, working, walking, playing or socialising in the area in which they operate. ITS can:
Benefits for some may come at an acceptable or unacceptable cost – depending on the interests of the community or stakeholder groups. Identifying the communities affected is important in identifying who benefits from what ITS measures whether they be:
Many ITS deployments will benefit a number of communities. For example, better freight management can benefit:
For inter-urban roads, the community benefits arise from a whole-system application of ITS whose primary aim is to manage flows in a wider motorway and road network and to manage and reduce the congestion impacts of incidents and emergencies. Community benefits will include reducing traffic, delays, pollution, safety and better emergency response. The stakeholder groups benefitting may be quite dispersed – even people living a few miles from a major highway may experience noise pollution.
In the urban area, the more obvious community benefits from ITS are those arising traffic and mobility demand management. ITS which manages traffic and public transport combine to:
The UTC system introduced in Paris, France, included reducing the waiting time for pedestrians crossing at signals and extending crossing time, and adjusting signal times to suit cyclists. It has made the area safer for pedestrians and cyclists, and at the same time reduced the time which vehicles spend in traffic by 15%.
In Trondheim, Norway, toll ring and traffic management measures were deployed, reducing vehicle traffic in the city centre. The change in mix of traffic on some routes reduced accidents by 60-70%
An electronic parking guidance system was installed at O R Tambo International Airport, South Africa to deal with the significant problems of congestion on the roads leading to the airport and within the airport itself. Major benefits included a 70% reduction in fuel emissions and a reduction in the average time to find a parking space – from 8 minutes to two and a half minutes (See http://www.itsinternational.com/sections/cost-benefit-analysis/features/intelligent-parking-guidance-relieves-congestion-reduces-costs/)
ITS helps policy-makers, transport authorities, road network and public transport operators to do a better job – helping to deliver their transport objectives. For example, if one of the objectives of a city’s transport policy is to:
Investment in ITS can help them to deliver safer and more reliable journeys, reducing the detrimental effect on the environment, giving priority to freight transport, commuter traffic, public transport or pedestrians. It does so by helping to manage a city road network – and balancing many conflicting priorities. These might include the competing needs of residents, commercial retailing, tourism and the environment, as well as ensuring mobility for people without their own personal means of transport and making transport accessible to vulnerable road users.
One of the key benefits of ITS for policy-makers and transport professionals is that, embedded within ITS is the ability to gather and process large amounts of data and information – which can be used in decision-making on future planning and ITS investments. (See Project Appraisal) For example:
Investment in new road infrastructure has been important to accommodate demand but has often been unable to keep pace. ITS has a role to play in ensuring efficient and safe use of the infrastructure – smoothing traffic flows and improving journey times – and can help postpone the need for further new road building. (See Benefits to Road Network Management)
The benefits gained from deploying ITS will be outstripped by traffic growth within a few years, unless the measures are part of a wider mobility and transport policy – for example, including traffic restraint, congestion pricing or public transport priority.
Controlled Motorways use active traffic management to automatically regulate traffic speed limits in real-time in response to prevailing traffic levels on the motorway. It has delivered significant benefits. Drivers perceived that the steady flow of traffic at 50 mph (80 km/hour) resulted in overall time savings in comparison with the stop-start of motorways on which people drive at speeds varying from 30 mph to 90 mph (50 – 145 km/hour). (Case Study: M42 Active Traffic Management)
When the circumstances are , ITS applications – such as route planning, navigation, and VMS signing – can provide useful tools for road users to optimise their journeys.
Improving the efficiency and sustainability of transport is a major goal of all ITS programmes around the world. ITS is commonly deployed to deliver improvements in network capacity, traveller mobility, economic productivity and policy-related goals.
There are significant supply-side (network provider) benefits of using ITS for highways management to make best use of road capacity and increase throughput. For example, lane management have been one of the outstanding successes of ITS. This includes High Occupancy Vehicle (HOV) lanes, reversible flow lanes, variable speed limits and enforcement systems. These maximise the use of the infrastructure available, saving or postponing the very large costs of expanding road networks. (See Traffic Control Measures)
Capacity, as defined by the US Transportation Research Board, in its Highway Capacity Manual, is the maximum hourly rate at which vehicles or persons may be expected to traverse a given point – or uniform section of a roadway – under prevailing roadway, traffic, and control conditions.
Throughput is defined as the number of persons, goods, or vehicles traversing a roadway section or network per unit time – and so is very closely related to the concept of capacity. (See http://hcm.trb.org/?qr=1)
Improved vehicle control systems (crash avoidance systems) will increase throughput by reducing the headway required between vehicles. They can also help reduce the number of collisions, which means fewer traffic hold-ups. It has been estimated that a three-fold increase in throughput is possible with platooned vehicle operation. A less sophisticated automated highway system might increase throughput:
Improving mobility by reducing delay, minimising congestion and improving travel reliability is a major goal of many ITS applications. (See Traveller Services) The actual efficiency benefit to the traveller depends on the context. For example:
Travel time savings will depend on levels of congestion and available opportunities for diversion. Among the most common measures is delay – which itself can be quantified in different ways – such as:
Direction and route finding information will generally have value regardless of congestion but there may be potential disbenefits from use of unsuitable roads, especially by heavy goods vehicles. (See In-vehicle Systems) Pedestrians can also benefit in terms of reduction in wasted time waiting to cross streets through smart signal controls. (See Safety of Vulnerable Road Users)
Pre-trip traveller information has benefits for journey planning – in terms of better routeing, knowledge of interchange between modes, or overall journey times. Better informed travellers are able to choose alternative routes and modes, switch to public transport, and save time. (See Travel Information Systems)
While travel cost reduction is of interest to all road users, the benefits associated with ITS are most tangible to the operators of vehicle fleets. ITS productivity benefits have been assessed from the perspectives of fleet managers, transport authorities, and toll agencies. ITS options include automatic vehicle location (AVL) and computer aided dispatch (CAD) using sophisticated logistics software and close communications between the dispatcher and the driver. Each individual intervention appears marginal, but the overall effect in journey time reliability and time savings can make the difference between hitting a Just-in-Time delivery slot and missing it. In the USA, advanced routeing and decision-making software and organisation for the routeing of time-sensitive deliveries increased deliveries per driver hour by 24%. (See Freight & Delivery Operations)
In freight transport, there are two separate streams of benefits available from ITS:
The first benefit stream concerns the operation of supply chains using data and information linked with communication technologies. Methods include control systems, vehicle tracking and load monitoring – to:
The second benefit stream concerns reducing the costs of transport operators by providing productivity improvements:
The primary measure of productivity is typically cost savings as a result of an ITS implementation.
Canada’s Pacific coast’S BUS OPERATOR, Metro Vancouver’s TransLink, has gained substantial annual benefits in bus idle time savings from a new business intelligence-based solution. This is built on service running data that was already being captured by its ITS-based fleet management system. It achieved avoidance of costs estimated to be CAN$2.62 million. (See Vancouver Savings on Bus Idle Times)
ITS can support policy objectives such as sustainable transport – for example:
These options are becoming central elements of transport and regional economic policy – with the aim of attracting and maintaining investment and ensuring an attractive working and living environment.
The World Bank reports that every year, over 1.17 million people die in road traffic accidents around the world, most of them – some 70% – in developing countries. Two thirds involve pedestrians – and, of these, one third are children. Over 10 million people are seriously injured each year.
Road traffic accidents cost countries between 1% and 3% of their annual gross national product (GNP) - a particularly heavy burden on those with developing economies.
ITS applications have the potential to significantly reduce road traffic accidents and their impacts in various ways that reduce the number, frequency and severity of incidents. For example ITS applications can:
ITS technologies for improving road safety include:
Performance measures that can be used to assess ITS benefits can be direct or indirect.
Direct measures include overall crash rate, fatality and injury rates – for example, percentage reduction in collisions (but this is difficult to obtain empirically from operational tests since real accidents in field trials are infrequent)
Indirect measures include vehicle speeds, speed variability, the number of traffic violations, percentage reduction in rescue response time and public perceptions.
A few multi-year longitudinal studies have provided reliable before-and-after data on the impact of ITS on accident rates. For example:
Safety benefits from ITS go wider than measurable accidents. The confidence that travel is safe does not come only from measurable benefits such as reducing accidents or collisions and their consequences. The perception of personal safety is also important. Many countries now have policy priorities relating to perceptions of personal safety, whether that is nervousness about traffic, crime, isolation or a wider perception of community safety.
People are fened of traffic, even if they have never been involved in an accident or collision. This fear has societal costs. ITS can:
Access control and area management schemes have been successful in improving the quality of city centres. For example, in the 1990s, ITS-based security measures in the City of London significantly reduced the number of accidents involving pedestrian.
A number of ITS-enabled measures and technologies have an important part to play in delivering safety benefits.
One of the driving forces behind the development of ITS in Europe has been the level of road traffic accidents across the continent.
The European Commission estimates that there are some 100 million cross-border road trips annually within the European Union (EU), and that foreign drivers account for 5% of traffic – but commit 15% of speeding offences. EU countries work together on cross-border road safety enforcement.
Since 7 November 2013, most EU countries have been implementing cross-border enforcement for the riskiest traffic offences – such as, speeding, failing to stop at traffic lights, failure to use seatbelts and drink driving. These account for 75% of road traffic accident deaths in Europe. The enforcement scheme operates through ITS-enabled electronic exchange of national vehicle registration data with other countries. It is estimated that public awareness of the increased likelihood of offenders being caught will save between 350 and 400 road traffic accident deaths a year.
Red-light running is a major traffic safety issue. In the USA, it is accounts for some 800 deaths and an estimated 165,000 injuries a year. Automated camera enforcement provides the evidence necessary for prosecution.
The city of Bologna in Italy has tested an automatic enforcement camera-based system (known as STARS) to help detect traffic light offences and issue fines for non-compliance. The images are stored as a source of court evidence and for statistical evaluation.
Following its installation, accidents fell by 21% and injuries by 28% at all equipped crossings. The number of fines initially increased significantly - by 88% over the period between 2008 and 2011 - but subsequently stabilised. In comparison with data from the year before installation to August 2011, there was a total reduction of 40% for accidents and 48% for injuries.
Drivers, who did not know where the STARS system was active showed increased caution at all intersections – extending the beneficial effects of the technology while reducing its installation costs.
Speed enforcement is becoming more sophisticated and driver-friendly. Conventionally the main technique has been the use of single-point “spot” speed cameras, which record the driver exceeding the limit as they pass by. In the UK, speed cameras of this kind have often drawn hostility from motorists who perceive it as an unfair means of raising money from enforcement fines.
Speed over distance (SOD) or average speed enforcement (ASE) are seen as fairer methods.
Average speed enforcement is demonstrating higher levels of compliance than spot-speed in a number of European countries where it has been deployed.
“Soft” speed enforcement aims to influence driver behaviour – it does not impose legal or financial penalties. A European example involves detecting a vehicle as it approaches from a measured point ahead, which allows the time needed to cover the distance to be calculated to determine whether the vehicle is speeding. This can trigger a dynamic message sign to display a warning message. (See Vulnerable Road Users)
Many countries are introducing and enforcing 32km/h speed limits in urban areas – to protect vulnerable road users, such as children. In Chicago, USA, where 800 out of the 3,000 pedestrians hit by vehicles each year, are children, and signage is ignored by 10% of motorists – the system lowers camera speed triggers during enforcement hours More information here: http://www.cityofchicago.org/city/en/depts/cdot/supp_info/children_s_safetyzoneporgramautomaticspeedenforcement.html)
Beneficial ITS vehicle technologies include:
The basis of all these systems, and the safety benefits that they bring, is the development of on-board sensors linked to the vehicle’s engine management and braking systems. (See Driver Support)
Anti-lock braking systems (ABS) intervene to help stop loss of vehicle traction (skidding – for example, in icy weather or wet conditions). ABS works closely with electronic stability control (ESC), which detects the loss of steering control and applies the brakes individually to the wheels to correct the steering. The US Insurance Institute for Highway Safety and the US National Highway Traffic Safety Administration estimate that comprehensive use of the technology could avoid one-third of fatal road traffic accidents.
Crash avoidance systems use autonomous braking, which comes into effect if a driver fails to brake in time. The technology is an advance on the (widely-used) autonomous cruise control, which automatically adjusts a vehicle’s speed to keep it a safe distance behind traffic ahead. Both the US and the EU are moving towards making mandatory, the fitting of frontal collision warning systems. Automotive manufacturers have started to include these systems into their production lines. The EU estimates that these will save 5,000 deaths and 50,000 serious injuries a year.
Automatic parking uses sensors to detect the presence of objects around a vehicle to guide the vehicle safely into a clear space.
Driver drowsiness detection is a response to studies that suggest that up to 20% of road traffic accidents are due to fatigue. It works by monitoring a vehicle’s movements and assessing the likelihood of these being controlled or uncontrolled.
The main ISA options are:
Trials indicate the potential for safety, efficiency and improvements – including 42% reductions in fatal crashes, fuel efficiency gains of 5%, and smoother traffic flows resulting in less congestion (See: http://www-nrd.nhtsa.dot.gov/pdf/esv/esv20/07-0247-W.pdf).
Widespread adoption of ISA could bring the additional benefit of reduced insurance costs. In Europe, ISA systems that meet European New Car Assessment Programme (Euro NCAP) requirements gain an advantage in relation to the car’s overall ‘Safety Assist’ rating.
Automatic Incident Detection (AID) systems use cameras and traffic monitoring technology to record and analyse traffic data and quickly detect incidents using motorway incident detection systems. A sudden build-up of congestion, for example, can indicate that there is an incident ahead.
Response times to road traffic accidents and medical emergencies are critical, with the ‘golden 15 minutes’ typically cited as the optimum window for early and effective treatment. The key needs are fast response and accurate direction to accident scenes. Automatic traffic signal priority for emergency vehicles is increasingly common.
ITS technologies introduced to speed up the process include automatic crash notification systems, which many automotive manufacturers are building into their vehicles. These work by sensing an impact and sending out an automatic alert via mobile phone networks to a call centre. In Europe, the EU’s eCall (emergency Call) initiative aims to mandate, from 2018, European automotive manufactures to install these systems.
Emergency service providers can make use of real-time dynamic route guidance systems to dispatch and route vehicles around known congestion and roadworks to minimise response and return times. Speeding ambulances, themselves, risk causing, or being involved in, road traffic accidents. The US General Services Administration records over 6,000 ambulance crashes a year. In-vehicle ‘black boxes’ can monitor and record driver behaviour and highlight training needs.
Workzone traffic management schemes can draw on ITS technologies such as Bluetooth detection, which anonymously registers the passing of vehicles carrying Bluetooth devices (See Wireless Telecommunications). This provided the US state of Texas with a cost-effective alternative for monitoring the speed of vehicles over a lengthy section of road reconstruction on the I-35 highway.
There are examples of basic roadworks equipment being equipped with ITS features to provide a safety role. For example:
In rural areas, intersection crashes typically occur less often than in urban ones. They are often more severe because of the higher vehicle speeds and the consequences can be more serious because of longer emergency response times. New intersection decision support systems use traffic sensors and advanced computing to monitor vehicles moving along rural divided highways (dual carriageways). They process the data generated to alert drivers waiting to merge with, or cross, the traffic – when the gaps are too short for them to be able to do so safely.
In Australia, where about 60% of all fatal road crashes occur on rural roads, there is research evidence that electronic stability control (ESC) can help avoid crashes on high-speed routes, by detecting when a vehicle is at risk of skidding and applying preventive braking interventions to individual wheels. In 12 modelled crash scenarios developed from data on actual crashes, ESC prevented collisions in 10 cases and reduced their severity in the other two.
Collisions with wild animals on rural roads are increasing wherever human development spreads. This is an issue of growing relevance to developing and emerging economies. A crash involving a large animal can cause death, serious injury, severe vehicle damage and disruption to other road users. Physical defences such as fencing and over/underpasses are not always possible or cost-effective, given access and maintenance issues. In-vehicle and roadside systems are being developed to detect large animals. The sensors can distinguish between moving vehicles (with warm engines) and animals, alerting drivers to their presence (See Information and Warning).
Planners are increasingly concerned with climate change and ‘greenhouse’ gas emissions. Transport is a major source of pollution which has health and quality of life implications. ITS can help ameliorate – for example, by smoothing traffic flows, reducing energy consumption and vehicle emissions. Performance measures for assessing the impact of ITS include reductions in emission levels (Carbon Monoxide, Nitrogen Oxides and Hydrocarbons) and better fuel economy.
In most situations, local analysis and simulation are needed to estimate the environmental benefits of a specific ITS project (See Project Appraisal).
It is difficult to measure environmental impacts on an entire region because of the large number of other variables including local terrain, road geometry, weather and contributions from non-mobile sources. For example:
The potential application of ITS to address environmental and societal challenges is an increasingly important emerging area. The main challenges being addressed are:
The enforcement of vehicle emissions legislation – such as the Euro standards introduced in Europe in 1993 and subsequently adopted in other parts of the world – encourages the use of cleaner road vehicles. It does so by putting pressure on operators to accelerate vehicle replacement or to fit their existing vehicles with pollution reducing equipment. In Berlin, the share of compliant diesel-engine vehicles rose by 38% between 2006 and 2011 – largely because fleet operators installed diesel particle filters.
The cost of setting up the London (UK) LEZ was comparatively low because it made large-scale use of the city’s existing congestion charging infrastructure. Creating an LEZ using existing enforcement infrastructure – as in the London case – makes economic sense.
Analysis of Australia’s Sydney Coordinated Adaptive Traffic System (SCATS) has identified reductions of 15% in CO2, 13% in NOx and 15% in PM10 emissions from vehicles – as a result of reductions in travel times of 28% and traffic stops of 25%. Case Study: Sydney’s Coordinated Adaptive Traffic System
CO2 and noise emissions often respond to similar solutions:
Demonstrations in the West Midlands of England have shown that the use of night-time variable speed limits (VSLs) on sections of managed motorways near to residential areas can deliver worthwhile noise reductions without affecting journey times as much as in daytime.
There are ways to mitigate the visual impact of ITS equipment. For example:
In time, it is possible (with good design and appropriate technology) that cooperative vehicle systems may reduce the need for invasive ITS installations on roads – since they will automatically collect, process and transfer data and traffic information between vehicles, the roadside and drivers.
When people and businesses relocate the more well-informed they are about transport options, the more likely they are to opt for well-connected locations. In North America, Australia and New Zealand, neighbourhood rating systems and journey planning which makes use of data from public transport operators, cyclists and pedestrians to highlight areas with good facilities.
ITS can also be used to manage and monitor environmental zones. For example, DMS and VMS can be used for signing the zone, especially if different access regimes apply to drivers at different times. ITS can also be used in air quality monitoring and in communicating the results to stakeholders. Example of these are:
Santander, in Northern Spain, has a population of 180,000. It is deploying some 12,000 electronic sensors or ‘nodes’, fixed to buses and buildings, to measure a variety of parameters, such as noise, temperature, ambient light levels, carbon monoxide concentration, and the availability and location of parking spaces, for efficient city management:
Santander’s innovative approach has contributed to a decision by Spanish multinational transportation infrastructure investor, Ferrovial, to invest in the city and develop a Research Centre for Intelligent Cities – in parallel with the company’s cooperation agreement with the Massachusetts Institute of Technology (MIT).
ITS has been used as part of a coordinated approach to promote travel choices that will help reduce congestion and pollution in cities. It provides:
Car pooling (also known as ride-sharing) and car clubs are enjoying a boom, thanks to ITS technologies. ITS applications such as a car pool database (of drivers offering spare seats and potential passengers looking for a ride) – together with a user forum – can enable planned sharing of car journeys. Car pooling reduces individuals’ fuel, parking and toll costs – and in the USA, allows them use of dedicated high-occupancy vehicle (HOV) lanes. It helps to reduce traffic demand, cut emissions and relieve the pressure on parking. Employers can offer and promote schemes as an incentive to their workforces.
Car clubs provide members with the use of a car on an as-needed basis for specific journeys – delivering them savings on insurance, depreciation and road taxes. Local governments around the world are promoting schemes on their travel websites as making useful contributions to modal shift. Booking is by phone or internet. For some schemes, a member’s smartcard opens the vehicle and is used to process payment for use and fuel from the member’s account. Transport for London calculates that those driving fewer than 9,600km a year can save up to £3,500 as compared with owning a car.
Cycling is gaining popularity worldwide as an alternative travel mode, one that is attractive on personal and public health grounds. On busy urban roads, cyclists are vulnerable – particularly prone to collisions with heavy goods vehicles (HGVs) overtaking or making turning movements at road junctions. ITS-enabled protective systems being investigated include:
Various organisations engage in road network management. They include the town, city and regional authorities for road networks at every level. There are control centres dedicated to managing the traffic control systems for urban networks, motorways and other strategic roads, as well as for toll roads, tunnels and bridges. Each organisation will have a different perspective on the significance of ITS applications and services but most stand to gain some improvement in network efficiency, for example:
In these ways, the community’s requirements for mobility and commerce can be met more effectively and the need to construct new or expanded roadway facilities can be reduced:
The benefits of ITS for road network management can be considered under a number of headings:
Urban traffic Control (UTS – also known as Area Traffic Control) is one of the world’s longest-established ITS applications, with its origins in the 1970s in response to growing car ownership that led to congestion on city streets. UTC provides the means to monitor road traffic flows in built-up areas, and modify these in response to congestion and other conflicts (for example, the balance between public transport and private cars). One way is by automatically adjusting traffic signal phases at intersections in response to flows and the needs of public transport vehicles (See Urban Traffic Control).
Widely used UTC systems around the world include:
UTC installations form the core of more developed and sophisticated arrays of urban ITS applications that expand their functions by linking in additional capabilities. They do this by introducing common databases and data dictionary, allowing the mechanisms (such as cameras and sensors) used for traffic management, parking management, traffic signal control for priority for buses, air quality management in response to pollution, and weather monitoring to communicate and share information with each other via a single, integrated control centre (See Urban Networks).
Major benefits include:
Central to integrated operations is the adoption of agreed open standards and specifications for products across the ITS industry, to ensure their interoperability. Open specifications make it possible easily to add fresh functions when needed, and free local governments from dependence on individual suppliers when it comes to needing replacement parts or system upgrades. Agencies can then shop around for the most competitive prices and service offers, which in turn stimulates innovative commercial development (See ITS Standards).
Smart parking deployments give car park operators and city governments useful data on levels of demand. They can use this information to adjust charges, levying higher rates to increase turnover on their busiest sites, and lower ones to attract drivers to underused spaces.
A San Francisco system gives drivers real-time information on the occupancy and cost of over 19,000 city-owned parking spots. Drivers can use information on the parking charge, location and time to make their choice. Smartphone apps can help them find a space within an easy walk of their destination. A number of automotive manufacturers are also developing their own in-vehicle parking information systems.
US researcher Professor Donald Shoup has calculated that search for kerb parking in a 15-block city district can created about 1.52 million excess vehicle km of travel. This translates to 177,600 litres (47,000 US gallons) of wasted fuel and 73 tonnes of excess CO2.
Figure 1- Ramp Metering (courtesy of Highways England)
Highway management systems include automatic incident detection, CCTV for the benefit of control centre operators, automation of traffic flow monitoring and software to control speed limits before queues occur. Case studies have shown the delay-savings benefits achievable from the strategic use of variable message signs (VMS) give a positive cost-benefit which justifies the initial capital investment. For example, queue protection systems deliver significant socio-economic benefits from reducing numbers of killed and seriously injured road-users. They also produced significant secondary benefits through incident-delay savings (See Highway Traffic).
Savings from cost reductions in journey times are important to all road users, but the benefits are most relevant to the operators of vehicle fleets and highway infrastructures. The quantifiable benefits come in one of two ways:
In the USA highway management techniques commonly include high occupancy vehicle (HOV) and high occupancy toll (HOT) lanes on motorways and expressways.
HOV lanes, introduced in the US in the 1970s and later adopted in Australia and New Zealand – though rare in Europe - are open to cars carrying at least two passengers (for example, in car sharing schemes), and buses and, sometimes, green (low emission) vehicles. The aim is to increase higher average vehicle occupancy and person throughput with the goal of reducing traffic congestion and air pollution. Some HOV lanes are reversible, to accommodate differing peak flows.
HOT lanes give drivers of single-occupancy vehicles access to HOV lanes on payment of a charge levied by, for example, by automatic number plate recognition, or electronic fee collection (EFC). Tolls can increase in line with traffic density as this increases within the lanes, to reduce the risk of their becoming congested.
In the Los Angeles HOT system, drivers use specially-developed "switchable" transponders to indicate the number of occupants. The EFC reader that picks up the setting uses it to decide automatically on chargeability. For enforcement, a beacon near the EFC reader lights up in response to the scanning and alerts highway patrol officers to check the stated occupancy setting.
So-called “Smart” or managed motorway sections use ITS technologies for active traffic management to control flow and speeds and give users relevant information on overhead variable message signs (VMS), to help them make the best use of heavily congested segments. They can impose variable speed limits (VSLs) where the speed limit is altered to reflect current traffic conditions.
Traffic sensors detect slow-moving and stationary traffic and alert HA regional control centres to the changing conditions. These set relevant VMS messages and variable speed limit signs (VSL) to correspond with traffic movements. The “Dynamic Roadspace Utilization Manager (DRUM) is another good example of ITS software application that has been applied to great advantage during contruction works on an active motorway. The principle is based on first cone-on and last cone-off approach to road work closures.
See: http://trl.co.uk/software/software_products/drum.htm
Initial versions enabled the temporary use of the hard shoulder as an extra lane (“hard shoulder running”) when traffic built up, with Variable Speed Limits (VSLs) in force and VMS advising drivers accordingly. Emergency refuges were available at regular intervals.
The more recent design aims to deliver the same benefits for a lower whole life cost. The hard shoulder is available for use as a running traffic lane at all times, so permanently delivering extra capacity. On the London Orbital M25, enforced VSLs and a reduction in lane switching has successfully improved the capacity of the motorway without needing to increase the number of traffic lanes. Other countries are now adopting the idea.
Case Study (See Active Traffic Management)
Freight consolidation centres (FCCs), located at points close to town centres or shopping malls and major road junctions, help to avoid or reduce the impact of Heavy Goods Vehicles (HGVs) on urban roads. They can help mitigate traffic congestion and may have a positive impact on local air pollution. Using logistics tracking and tracing systems, they take in large incoming consignments destined for numbers of in-town retailers, for breaking up into individual loads. These then travel on by smaller and less polluting vehicles at convenient times over the final leg. There are currently over 114 FCCs worldwide, mostly in the EU – specifically France, Germany, Italy, the Netherlands and the UK.
A system deployed in the Netherlands and elsewhere in Europe rewards truck drivers whose driving is environmentally-friendly with green lights at intersections. It interfaces with the city’s signal control network and incorporates data on cities’ speed limits, encouraging compliance with these by integrating with trucks’ own engine management system for speed limiting and acceleration monitoring. A dashboard display keeps drivers informed on their performance and fuel consumption and driving performance, with low scores generating warnings.
Commercial drivers and their vehicles can be a reliable source of information on current traffic conditions the network. Increasing use of just-in-time deliveries means that vehicle fleet operations managers and drivers are increasingly interested in the real-time status of urban road networks.
The Bristol Freight Consolidation Scheme in the UK delivers to 115 businesses. It has reduced deliveries by 80% and achieved a 130 tonne reduction in CO2 emissions by use of two nine-tonne electric trucks which recharge at the centre at night. These return with recyclable waste. The reduced traffic congestion is predicted to deliver social benefit gains worth up to £2 million over five years.
(See Case Study: Broadmead Freight Consolidation Centre (UK))
Overweight and over-height vehicles pose real threats to road safety and transport infrastructure. Systematic enforcement against overloading of trucks is a cost-effective way of reducing damage to the road pavement. Weigh-in-motion systems save trucks time by checking their safety status as they drive over measurement plates at highway speeds. In the US, a developed version also checks trucking company and driver credentials by automatically accessing electronic data banks, enabling officials to focus on trucks that are likely to be suspect and achieve higher success rates. The US DOT estimates that manual checks can save around 0.7% of road traffic accidents involving trucks (approximately 440,000 each year). Automated screening can improve this to above 3.5% (See Weight Screening).
Concern for the impact on Australia’s road infrastructure (notably bridges) of increasingly heavy trucks has led to the regulatory Intelligent Access Programme (IAP) which restricts use by heavy trucks of the country’s road network.
It allows over-dimension vehicles access to normally restricted routes, in return for their carrying an on-board device that uses satellite-based tracking technology to monitor their compliance with IAP conditions and sends their locations to a control centre for analysis.
IAP enables qualifying road freight transport to increase its productivity by taking faster and more convenient routes, while controlling overall truck impacts on the road network and deterring non-qualifying vehicles.
Successful management of a major event requires close coordination between all parties: the event promoters, the authorities for roads and highways that are affected, the police, emergency services and transport operators. There may be heavy reliance on ITS – for example VMS to keep travellers informed about current options and CCTV to assist the network controllers in their tasks. At the same time, costs of additional equipment that may be needed for only a short period for non-recurrent events demand careful scrutiny (See Planned Events).
When the German Federal Agricultural Show organisers chose the medium-sized city of Koblenz as the location for 2011 the city had to plan for an additional 40,000 visitors a day over a six-month period. The city needed to expand it traveller information service and make it available on a regional basis.
The solution adopted, in coordination with the regional government, was to extend an existing regional, motorway-based intermodal traffic information system and expand the scope of its mobility web portal to cover urban as well as motorway traffic (See www.verkehr.rlp).
The city also needed to generate information for displays on VMS. The city could not afford to buy all the new traffic cameras that it would have needed, so it contracted a traffic information supplier to provide floating vehicle data (FVD)-based output to measure travel times and speeds. FVD involves anonymously monitoring moving vehicles that are equipped with, for example, Bluetooth-enabled mobile phones, turning them into mobile traffic sensors for notifying traffic conditions.
The project has raised interest in other German cities which have adopted elements of the approach. It has demonstrated the value to local governments of buying dynamic data from private traffic content providers. Bought-in traffic data proved to be a cost effective alternative to additional conventional traffic cameras.
At the 2012 London Olympic and Paralympic Games the successful operation depended heavily on effective traffic management on the critical Olympic Road Network (ORN) with traffic lanes reserved to give priority access to the 80,000-strong Olympic ‘family’ (so-called ‘games lanes’).
To monitor the network, Transport for London (TfL), the UK capital’s multimodal transportation agency, upgraded 1300 traffic signals and deployed 1400 CCTV cameras, some newly installed, others operating through data sharing arrangements with individual local authorities.
Case Study on Mobility Management for Major International Events
Over and above its main aim of safety, V2I can help to reduce the delays and congestion resulting from road traffic accidents. V2I keeps vehicles in electronic contact with the roadside infrastructure, not only to help avoid crashes but also decrease the environmental impacts of traffic by smoothing traffic flow and minimising rapid accelerations and decelerations. One specific benefit being piloted is the ability to transmit traffic signal phase and timing information directly into the vehicle at upcoming intersections.
The eCall system is an example of connected vehicle technology. A broken-down vehicle – or a vehicle involved in a collision – if vehicle fitted with eCall can send an automatic message about its location, description and the vehicle condition as the event occurs. This can aid prompt detection and rapid clearing of the affected road section to make the area safe for other traffic. The overall benefit is more efficient network operations. The automotive industry is now developing a range of services to lower the cost of dedicated unit installed for the purpose of archieving eCall.
With V2V, vehicles ‘sense’ potential dangers by means of detectors that determine the presence of other vehicles, their positions and speeds. The on-board systems will then warn drivers and/or intervene automatically in engine management or braking systems, to avoid an accident.
Eventually, the hope is that V2V and V2I will reduce both the quantity and size of roadside infrastructure, by sending important safety- and mobility-related information directly into vehicles (See Warning & Control System).
Road users and transport operators want roads that are well-maintained and in good condition and – if at all possible – available for travelling on in all weathers. In this respect the resilience of the road infrastructure itself is an issue. Bridges and safety barriers are vulnerable to vehicle collisions and the road pavement itself may suffer damage from adverse weather, landslides, overloaded vehicles and constant wear and tear. Special measures may have to be put in place to deal with network security to ensure operational resilience (See Network Security).
For monitoring individual ITS installations in operation, the concept of an ‘online filing cabinet’ for storing information can help road maintenance engineers progressively improve overall performance rather than simply reacting to faults being notified. There is even the prospect of locating wireless sensors into road surfaces, to gather and relay information on condition and maintenance needs.
The European Space Agency (ESA)’s “Live Land” project is investigating ways of reducing the exposure of the transport infrastructure to landslides and subsidence by developing a sustainable prediction, monitoring and alerting service. This would use earth observation and satellite communications to create a central management system.
In the USA freight carriers move an estimated 700,000 shipments of hazardous materials every day. Electronic access to carriers’ databases for early identification of the vehicle and cargo enables responders to:
In humanitarian relief supply chains, ITS plays a key role in the last 1km-2km delivery from a local distribution centre (LDC) to affected populations. Computerised management of available vehicles and planning of delivery schedules can optimise resource allocation and routing decisions with the aim of minimising transportation costs and maximising benefits for those in need. This can be particularly important for disasters in developing countries with inadequate road networks.
Existing traffic management systems can play vital supporting roles. Bluetooth-based traffic monitoring proved effective when a factory in Texas caught fire and later exploded. Residents needed immediate evacuation, with school buses and ambulances coming in to rescue them and needing priority access.
Japan has reacted to a series of natural disasters by developing a unified approach to the organisation of traffic management and emergency response, integrating automotive manufacturers’ and other sources of navigation and traffic information in a central disaster transport platform. One output is the creation of event- and location-specific online accessible route maps for use by trucks delivering relief and reconstruction supplies.
Particularly vulnerable are large numbers of passengers moving through confined spaces, for example, transport termini and interchanges – and metro stations. Passenger evacuation systems depend for their effectiveness on the amount and quality of information made available. Simulations can model individual passenger movements to provide for the needs of the elderly and disabled, and integrate planned lifts and escalators for the capacity calculations needed to estimate realistic evacuation times.
Prevention of terrorist acts can be strengthened by systems for the early detection of would-be perpetrators. Analysis of CCTV footage of rail and bus stations can detect people making unusual movements.
The US’ ‘Protect’ programme has developed a detection and alerting system for ensuring that a public transport operator knows within five minutes that there has been a biological or chemical attack, its location and the substances that have been used – five minutes being the limit for minimising numbers of casualties.
The Canadian city of Edmonton has successfully demonstrated a system for detecting explosive and radiological threats to public transport users by equipping ticket validating equipment to pick up traces from the hands of ticket carriers. On gaining a result, it automatically alerts the control centre and photographs the suspect. The system has worked flawlessly.
It is clear from media coverage that the changes that ITS interventions are intended to achieve are not necessarily apparent to, or welcomed by, all transport users. This means that agencies planning to introduce potentially controversial ITS technologies need to be well-prepared with convincing, evidence based arguments to communicate their aims. Examples are shown below.
ITS Intervention |
Policy Aim |
Public Perception |
Urban Road User Charging
(on existing routes using electronic fee collection technology) |
manage traffic demand and reduce congestion, time delays and pollution invest net revenues in better public transport to influence modal shift |
Public objections to being charged to use roads that the public has already paid for from its taxes |
|
|
Results: Urban congestion charging often scores badly in public opinion and referenda Public opposition is a deterrent to elected local politicians, who need voter support |
Success Story - London Congestion Charging: was politically achievable because it relied on a quickly-installed enforcement method - automatic, on-street numberplate recognition cameras to record vehicles whose owners were not recorded in the back-office database as having paid the charge. it was up and running, with its benefits becoming apparent, within a single four-year term of an elected mayor |
Success Story – Stockholm Congestion Charging: was politically achievable because it was implemented after a comprehensive public consultation its net revenues are used to part finance other infrastructure investments it was subject to a referendum held after its introduction |
ITS Intervention |
Policy Aim |
Public Perception |
Camera Enforcement: Red Light Running Speed Enforcement |
reduce the severity of accidents and save lives |
invasion of an individual’s privacy penalty fines viewed as hidden local government “taxation” red light camera enforcement has come under strong challenge in the US. |
ITS Intervention |
Policy Aim |
Public Perception |
Adaptive In-vehicle Speed Control technologies |
reduce the severity of accidents and save lives reduce the costs associated with accidents smooth traffic flows |
driver perception of loss of individual control |
The benefits of ITS are varied and not always directly calculable. For example, real time information systems on public transport are often introduced at the same time as bus priority measures which make the service faster and more reliable, and very often with new or refurbished vehicles:
The benefits of ITS can be assessed in three ways:
Preventing or reducing the severity of an incident saves emergency service costs, hospital and medical costs and losses to the economy thorough lost productivity. Often these are combined and quantified for Killed and Serious Injury (KSI) incidents and where possible need to be quantified for the country, location or highway being considered for the application of ITS.
Speeding up traffic in urban area by means of “smart” computer-controlled traffic signals or smoothing traffic on motorways to eliminate stop-start conditions will bring travel-time savings.
ITS can provide cash benefits in a number of ways – for example, by reducing the initial capital investment in road infrastructure, or by offsetting operational costs to achieve revenue savings. These are often termed as “real” money savings as opposed to socio-economic benefits:
Measuring customer satisfaction can be accomplished by asking whether the ITS product or service is delivering sufficient value or user benefit to outweigh the cost or investment in the product. This is often done through surveys.
ITS is expected to address the needs of not only the travellers but also transport operators, providers and managers. In most cases it may not be possible to assign a quantified benefit. Where results have been quantified – as illustrated in the table below – they can be a useful factor in supporting the business case.
Examples of ITS Benefits
There are many examples where the benefits of ITS have been measured. It is useful to consider both the aggregate and disaggregate benefits - that is to consider the impact the ITS investment will have overall, but also consider where the benefits will fall. Some benefits are in specific goal areas, such as safety. Others will be for specific groups of people, such as the rising population of mobile elderly and disabled people.
As part of its outreach, IBEC arranges sessions, seminars and workshops at World, European, Asia/Pacific and Pan-American ITS congresses and fora. IBEC sponsors sessions on this topic at the annual ITS World Congress.
IBEC also runs internal seminars and in-house training for organisations including the World Bank and the World Road Association (PIARC) and offers training materials in English and Spanish.
Membership of IBEC is open, with the aim of bringing together, and meeting the needs of, not only ITS professionals, but also transport planners, researchers, manufacturers and suppliers of ITS systems, decision-makers in public- and private-sector client organisations, as well as the transport-using public. This last is a very important audience, whose needs for ITS information are not always well catered for.
Members have access to a website library and information services. (See IBEC)
Intelligent Transport Systems (ITS) are a product of the revolution in information and communication technologies in the digital age. Today ITS supports the operation of transport networks that are integrated between road, rail, waterways, ports and airports. ITS also supports the control of vehicles that operate on those networks and efficient planning of the transport operations that use those vehilces (including individual journey planning and vehicle fleet logistics).
Intelligent Transport Systems include a wide range of user support functions, ranging from simple information alerts on a mobile phone through to highly sophisticated traffic control systems. To achieve its functions, ITS utilises a wide range of enabling technologies. These include:
At the heart of any Intelligent Transport System are the twin concepts of information and control technologies. Control technologies support many ITS applications and can be divided into two broad categories:
On the information side, technologies are needed to acquire data, process and fuse the data, make sense out of the data, and disseminate information to the users – including the travelling public. The information collected and processed can also be used to implement control and management measures aimed at improving network performance. ITS enabling technologies also collect real-time traffic and environmental data from the field and transfer the data collected to a central location where the data is processed, fused, analysed and used to support decision-making.
As with control technologies, detection technologies fall into two groups:
The fundamental requirement of Intelligent Transport Systems is data and information about the transportation network (roads and highways). Data needs to be reliable, up-to-date, readily accessible and sufficiently comprehensive for planning and operational purposes. This is the “info-structure” upon which so many ITS applications depend. Base data is usually map-related and held in digital format such as a database of road links that connect known locations, or “nodes” on the network – each with a unique reference. (See Planning Procedures)
As an absolute minimum, network information will consist of a “gazetteer” (or index) that holds the codes and short descriptions of the road links, nodes and other locations, such as:
A network gazetteer can provide a basis for a navigation database if it is sufficiently detailed. (See Navigation and Positioning)
The type of inventory required for ITS equipment and assets deployed across the network will be determined to a great extent by local operational requirements and the ITS applications to be maintained and supported. Information about the ITS equipment and its location will require some form of data management system and an appropriate method of location referencing to support the spatial representation of information. Maintenance Management Systems (MMS) and Communications Management Systems (CMS) are relational databases that can be used to maintain an inventory of ITS equipment and the associated communications infrastructure. Sometimes a performance monitoring system and/or a fault detection system is included. This monitors critical aspects of the equipment or system performance and issues alerts to the maintenance contractor when faults are detected. this monitoring equipment may be referred as Outstation Monitoring Units (OMUs) or a Performance Monitoring System (PMS).
Building on the network description, and using whatever location referencing system is adopted, a variety of data will contribute to the intelligence base for Road Network Operations. They include for each road link:
The network intelligence base needs to be kept current and up-to-date, taking account of any significant modifications to the road network that are:
Where network operations are well-developed a comprehensive database will be maintained of future events likely to have an impact on network capacity. This will require consultation with key stakeholders such as local authorities and the emergency services. (See Planning and Reporting)
Further layers of network information will be generated by the traffic monitoring systems. Data from traffic monitoring has three primary functions in network operations:
These basic functions will be served by information available from a variety of sources – and a systematic approach to traffic monitoring will be needed. An organised, planned approach is essential, especially if the data is going to be used for:
Automatic traffic monitoring systems will supply data in real time on traffic volumes, vehicle speeds, point-to-point journey times and, in some cases, vehicle classification. This data needs to be time-stamped and stored with reference to the link(s) to which they relate, together with a record of the data source. (See Traffic and Network Status Monitoring)
Computer models of the road network are used to forecast future traffic conditions and predict journey times. Modelling makes use of data on link characteristics, junction capacities and whatever traffic and incident-related data is available – which may be dynamic in real-time or historical. Model estimates can be compared with results from traffic monitoring to aid calibration and validation. A network model can also be used to forecast the effects of a given traffic management strategy and identify the potential benefits of that strategy compared to a “do nothing” scenario or an alternative response plan. Modelling can also perform risk assessments or sensitivity testing around different response plans.
Network modelling is able to deliver more efficient strategic traffic management by validating the decisions taken, and by providing better information for network management planning purposes. It can also help provide enhanced travel information for road users, such as more accurate journey times and forecasts of traffic conditions. (See Traffic Models)
Different methods are used to provide location information depending on the technology that is available and the accuracy required. Many countries have an established national grid referencing system which needs to be interpreted to give global latitude and longitude coordinates. Examples of location referencing include global positioning and the Radio Data System Traffic Message Channel (RDS-TMC).
Global positioning (Latitude/Longitude)
Global Positioning Systems (GPS) provide a means for determining an object's location, in terms of latitude and longitude, based on signals received from multiple Global Nautomatic gation Satellite Systems (GNSS) – for example GPS satellites at the location of the GPS receiver. Besides location, GPS can be used to track vehicles and can provide effective fleet management and monitoring the progress of a vehicle along its route.
Radio Data System Traffic Message Channel (RDS-TMC)
Some countries – mostly in Europe – have invested heavily in location referencing for digital radio, known as the Traffic Message Channel (TMC). Using RDS-TMC technology only 16 data bits (the smallest unit of data in computing) are allocated to location coding. This means that the RDS-TMC location code tables are only able to refer to significant highway junctions (nodes) and lengths of road (links). (See http://en.wikipedia.org/wiki/Traffic_message_channel)
ITS systems typically use multiple servers for the different applications, workstations, and video displays in traffic control centres. The computer hardware plays a major role in any ITS system. It is responsible for:
In addition to computer hardware, some ITS applications (such as freeway and incident management systems) typically include graphical displays in the control centre to provide a visual description of the transport systems operations, captured from field cameras.
Graphics can be provided on the monitors of control room workstations, or on large graphics screen displays in the form of a video wall. These displays provide the main “window” (or view) into the traffic management system – and are usually based on a graphical representation or map of the highway network. They will show the on-road assets available for network monitoring and traffic control, such as signals and VMS, location of Emergency Roadside Telephones (ERTs) and CCTV cameras.
Software and relational databases are required for ITS technologies to store, manage and archive network data. These are brought together as Archived Data Management Systems (ADMS) or what is sometimes called ITS Data Warehouses. ADMS offers an opportunity to take full advantage of the travel-related data collected by ITS devices in improving transport operations, planning and decision-making at minimal additional cost.
The technologies supporting ADMS are designed to archive, fuse, organise and analyse ITS data and can support a wide range of very useful applications such as:
The figure below shows an example of the system architecture designed for a simple ITS Data Warehouse being developed for the Buffalo-Niagara region in New York State USA. At the core of the system is a relational data base (such as Oracle or MySQL) which receives data from a wide range of sources including real-time traffic data (volumes, occupancies and speed), incident information, travel time and delay information, weather data, construction and work-zone information, and transit data (such as automatic vehicle location data). The relational database organises and fuses the data and information together – linking the different data streams through common identifiers – allowing a wide range of applications to be developed and deployed.
System architecture designed for a simple ITS Data Warehouse (Buffalo-Niagara Region New York State USA)
Among the data stored in ADMS are transport system inventory data, which can be used to facilitate the construction of detailed network models and traffic simulation models. Every link and associated junction in the network will need to be classified according to its strategic importance and capacity. Many ADMS are provided with functionalities that can convert the stored data into the required format for running different traffic simulation and analysis software.
A key benefit of having an ADMS is the ability to quantify network conditions in terms of travel times, speeds and traffic volumes. These measures, based on real-time traffic data, can be used to provide dynamic status information of prevailing network conditions and the “level of service” offered to road-users. Historical data of this kind, including information for incident detection and management and for traffic modelling, can also provide the basis for traffic forecasting and predictive information.
Tree-building algorithms:
Almost all ADMS now include a web-based graphical interface to support users’ queries. The interface is commonly based on Geographic Information Systems (GIS) technology. GIS comprise a set of computer software, hardware, data, and personnel – that store, manipulate, analyse, and present geographically referenced (or spatial) data. GIS can link spatial information on maps (such as roadway alignment) with attribute or tabular data. For example, a GIS-digital map of a road network would be linked to an attribute table that stores information about each road section on the network. This information could include items such as the section ID number, length of section, number of lanes, condition of the pavement surface, or average daily traffic volume. By accessing a specific road segment, a complete array of relevant attribute data becomes available.
The Graphical User Interface (GUI) shown in the ADMS architecture diagram above shows that the data archived in the ADMS can be accessed by different stakeholders over the Internet. Custom applications and reporting functions may be designed including performance measurement, predictive traveller information, traffic simulation model development support, and many other applications.
One of the primary functions of a road or highway network is to allow the safe passage of people and goods from their origin to their destination. Traditional sources of information (printed road maps, direction signs, route listings and journey plans) all have their place but satellite navigation systems are now used widely. Generically these are known as Global Navigation and Satellite Systems (GNSS). Specifically, they include the Global Positioning System (GPS) developed by USA, GLONASS, the Russian global satellite navigation system and GALILEO, the civilian global satellite navigation system being developed by the European Union from its precursor, the European Geostationary Navigation Overlay Service (EGNOS) (See Video).
The USA’s GPS consists of 24 satellites that are deployed and maintained by the US Department of Defence (USDoD). Originally, the system was used solely for military purposes, but since 1983 the USA has made GPS available for civilian purposes. For location determination (longitude, latitude, and elevation), a GPS receiver needs to receive signals from at least four satellites (signals from the fourth satellite are needed to correct for errors and improve accuracy).
A GPS on-board a vehicle – or a smart-phone with a GPS – can determine the location of the vehicle. The location can then be communicated via wireless communication to a central location (such as a traffic operations centre) for processing and data fusion. Besides pinpointing the location of a vehicle and communicating that location to a traffic operations centre, GPS receivers are at the core of all navigation-aid devices developed by companies such as Garmin, TomTom, and Magellan. For navigation and turn-by-turn directions, accurate digital maps are needed, in addition to the GPS receiver.
For its operation, the USA’s GPS relies on signals transmitted from the 24 satellites orbiting the earth at an altitude of 20,200 km. GPS receivers determine the location of a specific point by determining the time it takes for electromagnetic signals to travel from the satellites to the GPS receiver. A limitation of GPS is that it cannot transmit underground or underwater and signals can be significantly degraded or unavailable in urban canyons, in road tunnels and during solar storms. This is why there is continuing interest in terrestrial based radio-positioning systems using technologies such as mobile phones, Bluetooth and Wi-Fi.
GALILEO is the first complete civil positioning system to be developed under civilian control, in contrast to the USA’s GPS and the Russian Glonass systems. GALILEO has been designed with commercial and safety-critical applications in mind, such as self-guided automated cars. The first satellite was launched on 21 October 2011 and the system is scheduled to be fully operational before 2020. When fully deployed GALILEO will consist of 30 satellites (27 operational plus 3 back-up), circling the earth at an orbit altitude of 23,222 km. GALILEO will be fully interoperable with GPS and GLONASS and is expected to achieve very high levels of service reliability and real-time positioning accuracy not previously achieved.
Figure 3: The European Galileo satellite constellation [European Space Agency]
Digital maps are a pre-requisite for satellite navigation and many other ITS applications, such as automated driving and traveller information systems. Many technologies are currently available for creating and updating digital maps. For example, digital maps can be created by collecting raw network data, digitising paper maps, from aerial photographs and other sources. An initiative called OpenStreetMap (http://www.openstreetmap.org) intends to develop digital mapping for the whole world. The maps are developed from GPS traces collected by ordinary people and uploaded to the website. Aerial imagery and low-tech field maps are often used to verify that the resulting maps are accurate and up to date.
A navigation database is a commercially developed database used in satellite navigation systems. It is often based on a Network Gazetteer (See Basic Info-structure) and will contain all the elements needed to construct a travel plan or a route from a specific origin to a specific destination. Additional criteria may be added such as the route passes through a specific point, that it avoids tolls, that it is the fastest or shortest available, or that it minimises fuel consumption or emissions.
A navigation database is multi-layered and requires more than the basic coordinates for the road network links and nodes, although that is an important starting point.
Additional features necessary for navigation include:
Navigation databases also contain information on points of interest and landmarks, such as public transport facilities, major office buildings by name, hotels, restaurants and tourist attractions, post offices, government buildings, military bases, hospitals, schools, petrol stations, convenience stores, shopping centres and malls, toll-booths – and in some countries, the location of speed cameras.
Crowd-sourcing and social networking has enabled the creation of navigation databases that are adapted to the needs of specific groups of road-users, such as truck drivers and cyclists. There are also important developments taking place in pedestrian navigation.
Infromation on pedestrian navigation: http://www.insidegnss.com/node/513 and http://www.navipedia.net/index.php/Pedestrian_Navigation
Location-based services are computer applications that use location data to control features or the information displayed to the user. They have several applications in health, entertainment, mobile commerce, and transport. In road transport, for instance, location-based services can be used to provide point of interest information (using data held in a navigation database – such as the closest fuel station or restaurant. Location-based services can also be used to display congestion or weather information according to the location of the user (See Location-Based Services).
In co-operative systems, vehicles share data with each other and with the road infrastructure using vehicle to vehicle (V2V) and vehicle to infrastructure (V2I) communications. Vehicles that are connected in this way can make use of real-time information on moving objects (such as other vehicles nearby), and on stationary objects that might be transitory (traffic cones, parked vehicles and warning signs). This highly detailed, constantly changing information is held in a data store known as a Local Dynamic Map (LDM). The LDM supports various ITS applications by maintaining information on objects that influence, or are part of, the traffic. Data can be received from a range of different sources such as vehicles, infrastructure units, traffic centres and on-board sensors. The LDM offers mechanisms to grant safe and secure access to this data by means of V2V and V2I communications.
The data structure for the LDM is made of four layers:
Location referencing and object positioning for the upper layers of the LDM is complex and requires adequate location referencing methods. Since not all ITS applications need location referenced information, the use of this data is not mandatory.
These technologies allow the location of vehicles to be ascertained in real-time as they travel across the network. AVL has many useful applications for vehicle fleet management, such as improving emergency management services by helping to locate and dispatch emergency vehicles. AVL can be used for probe vehicle detection and on buses to locate vehicles in real-time and determine their expected arrival time at bus stops.
A number of technologies are available for AVL systems including dead reckoning, ground-based radio, signpost and odometer, and Global Positioning Systems. GPS is currently the most commonly used technology.
Another system for tracking and locating vehicles uses fixed point transponders which can read and communicate with other equipment – for example, toll tags on-board vehicles. These systems can determine when a vehicle passes by a certain point, and provide useful information on travel times and speeds.
A third method for locating vehicles is through mobile phone triangulation. The location of a mobile phone user is identified by measuring the distance to several cell phone towers within whose range the user is located. Using this technology, the location of the vehicle can be identified within an accuracy of about 120 meters. In rural areas, where few cell towers are located, the tower can measure the angle of transmission, which – along with the distance – can be used to locate the phone user even though the user might only be within the range of single cell phone tower. The estimated location in this case is not very accurate (within about 1.6 km).
A pre-requisite for Road Network Operations is the collection of accurate data that defines the status of road network, the traffic conditions that prevail and information about roadway conditions and the immediate environment. (See Planning Procedures) Data on traffic and weather conditions, incidents and other road and highway status alerts is used to provide intelligence for network operations activities, traffic control and information systems. This process of gathering data is called network monitoring, and can be undertaken by using a variety of means or a combination of them:
The extent and reliability of monitoring directly affects the amount of information available to plan operational activities and, in turn, the degree of management and control that is possible. It also determines the quality of information that is available to travellers and road users. (See Network Monitoring)
A number of steps are involved in the organisation of data processing and information supply. Together they form an information supply chain.
The first step is to acquire data about the status of the road network and the traffic using it, as well as other transport modes that connect with it. This data can come from a wide variety of sources including probe vehicles and roadway sensors such as inductive loops and microwave sensors, Closed Circuit TV (CCTV), webcams, video image processing, toll tag readers. It can be augmented with other information gathered from crowd sourcing and journalistic sources. Data mining techniques are applied to historical data to gain further insight into traffic operations and to provide predictive information on network conditions. (See Traffic & Status Monitoring)
Once the data is collected, the next step is to process it in ways that will yield useful information. This covers a number of basic functions:
The third step relates to the data analysis. This requires an appreciation of contextual relevance, processing of content to produce information according to user needs and preferences – including formatting the data for service. Data needs to cover the geographical area of interest and be checked for timeliness. Key issues are:
To provide predictive information, various time series analysis, data mining, mathematical modelling and Artificial Intelligence (AI) methods are used (See Data Aggregation and Analysis).
Various methods are used to disseminate the data that has been collected, processed and analysed. A variety of transmission media are available. For example, incident warnings and travel information is provided via many dissemination media, including data subscription services, travel news broadcasts, Highway Advisory Radio (HAR), roadside Variable Message Signs (VMS), internet websites and social media such as Facebook and Twitter. The security and integrity of transmission needs to be checked and maintained at all times. (See Traveller Services)
Information needs to be presented appropriately in response to user needs and the context of use. Good design of the user interface is essential. In traffic control centres, data may be displayed alongside CCTV camera images on a video wall or on-screen at operators’ work stations. Other stakeholders and the travelling public will use a range of devices to access information – such as desktop, laptop and tablet computers, mobile devices and smartphones, in-vehicle displays, public information points and kiosks. (See User Interfaces)
Issues may arise related to data ownership and intellectual property in respect to the use of public sector data versus commercial and proprietary data, information branding, value-capture, revenue and payment. (See Legal and Regulatory Issues)
An effective (and often extensive) traffic surveillance and monitoring system is a pre-requisite for any intelligent traffic control system to keep track of prevailing conditions across the network. A wide range of different sensors are installed in, on and above the roadway for this purpose and to obtain the necessary geographical and critical time coverage. They include inductive loops, non-intrusive traffic detection devices, video cameras and video image processing. Each technology has its own advantages and shortcomings – so the choice of sensor type for any ITS application will depend on what performs well in the prevailing environmental conditions, and its cost.
Traffic detectors (or vehicle presence detectors) are used in many ITS applications for – network monitoring, traffic control, speed measurement and automatic incident detection. Many different types of detection technologies are available. The following are typical technologies that have been developed to measure traffic data in specific locations and zones. (See Vehicle Detection)
Inductive loop detectors are currently the most widely used devices for vehicle detection, although microwave radar detection is also common. Their main uses are at intersections in conjunction with advanced signal traffic control systems, and on freeways for traffic monitoring and incident detection purposes. ILDs typically take the form of one or more turns of insulted wire embedded in the pavement. The loop is connected via lead-in cable to the detector unit, which detects changes in the loop inductance (changes in the in the magnetic field of the sensor) when a vehicle passes over it. ILDs can be used to detect a vehicle’s presence or passage. They can also be used to measure speed (by using two loops a short distance apart) and for classification of vehicle types. The main problem with using ILDs, however, is their reliability. Because ILDs are subject to the stress of traffic, they tend to fail quite frequently. Moreover, their installation and maintenance require lane closure and modifications to the pavement.
Inductive Loop Detectors
Microwave radar detectors are examples of non-intrusive detection devices whose installation and maintenance does NOT require lane closure and pavement modifications. Unlike inductive loops, non-intrusive detection devices are not embedded in the pavement. Instead, they are typically mounted on a structure over, or to the side of, the road such as the radar detection system in the photograph below. Depending on the type of electromagnetic wave used, microwave radar detectors can measure either vehicle presence, or vehicle presence as well as speed. They are also widely used to detect pedestrians waiting at pedestrian crossings.
One of the major advantages of microwave sensors is their ability to function under all weather conditions. Exceptions can be extreme weather such as sand-storms. Given that these sensors are installed above the pavement surface, they are not typically subject to the effects of ice and ploughing activities. Experience shows that microwave sensors function adequately under rain, fog, snow, windy conditions. Their main problem is that they can be obscured by tall sided vehicles – reducing their accuracy when they are installed at the side of the carriageway.
Non-intrusive Traffic Detector (Image courtesy of the IBI Group)
Infrared (IR) sensors are also non-intrusive detection devices. There are two types: passive and active detectors.
Passive IR detectors do not transmit energy – instead, they detect the energy that is emitted or reflected from vehicles, road surfaces and other objects. Passive infrared detectors can measure speed, vehicle length, vehicle counts and occupancy but their accuracy is affected by adverse weather conditions.
Active IR detectors emit a beam of Infrared energy which is reflected back to an IR receiver. They function in a similar way to microwave radar detectors – by directing a narrow beam of energy towards the road surface. The beam is then reflected back to the sensors – and vehicles are detected through changes in the “round-trip” transmission time of the infrared beam. Active infrared detectors supply vehicle passage, presence, speed, and vehicles classification information. They work well in controlled environments such as tunnels – and infrared can be used for safety purposes to detect over-heating vehicles or fire. Their accuracy is affected by weather conditions such as fog and precipitation.
Ultrasonic vehicle detectors function in a similar way to microwave detectors by actively transmitting pressure waves, at frequencies above the human audible range. These detectors can measure volume, occupancy, speed, and classification. Ultrasonic sensors are sensitive to environmental conditions. They require a high level of skill for their maintenance.
Vehicle traffic produces acoustic energy or audible sound from a variety of sources within the vehicle and from the interaction of the vehicle’s tyres with the road surface. Using a system of microphones, acoustic detectors are designed to pick-up these sounds from a specific area within a lane on a roadway. When a vehicle passes through the detection zone, a signal-processing algorithm detects an increase in sound energy and a vehicle presence signal is generated. When the vehicle leaves the detection zone, the sound energy decreases below the detection threshold and the vehicle presence signal ends. Acoustic sensors can be used to measure speed, volume, carriageway occupancy and presence. The advantage of acoustic sensors is that they can function under all lighting conditions and during adverse weather.
Similar to inductive loop detectors (ILD), magnetometers provide for point detection, but they differ from ILD in that they measure changes in the earth’s magnetic field resulting from the presence of vehicles. They can provide information on traffic volume, lane occupancy, speed as well as vehicle length. In general, there are two types of magnetometers:
Micro loops, (like inductive loops), require lane closure and pavement modification, with consequent delays to traffic. In recent years, the use of wireless magnetometers has received increased interest because of advances in battery technology which allow a unit to operate wirelessly for a period of 10 years before needing to be replaced.
Traffic Detector Video Training Course - Part 1 - Detector Theory
Traffic Detector Video Training Course - Part 2 - Detector Design
Traffic Detector Video Training Course - Part 3 - Detector Installation
Traffic Detector Video Training Course - Part 4 - Detector Maintenance
AVI can be used to identify vehicles as they pass through a detection zone. Typically, a transponder (or a tag) mounted on the vehicle can be read by a roadside reader as the vehicle passes by. This information can then be transmitted to a central computer. Currently, the most common road transport application of AVI technologies is in combination with Automatic Toll Collection systems (such as EZPass). With these systems, the value of the toll is automatically deducted from a driver’s account each time the driver goes through the toll plaza.
An important method of AVI, in common use, are ANPR (also known as Automatic Licence Plate Recognition - ALPR) systems which use optical character recognition technologies to identify and recognise vehicle registration plates. They typically consist of a specially adapted video camera linked to character recognition software. As a vehicle passes an ANPR/ALPR camera its registration number is read and can be checked against a database of vehicle records. There are two broad types of ANPR/ALPR systems:
With recent advances in computer hardware and software – processing in the field in real-time has become quite feasible (it typically takes less than 250 milliseconds). This avoids the cost associated with the need for large bandwidth to transfer images to a remote server.
Weigh-in-motion sensors are designed to measure and record axle weights and gross vehicle weights while the vehicle is in motion (driving – not stopped). WIM systems are attractive because they avoid the need to stop and weigh every vehicle. They have not eliminated the need for weighbridge sites for accurate weighing of trucks, but WIM acts as a filter and only vehicles which register an excess axle load need to be stopped and checked. The key component of any WIM system is the force sensor – for example quartz crystals produce electric charge when a force is applied along the vertical axis (the weight of the vehicle). WIM systems have several applications in ITS, especially as a part of an electronic pre-clearance system for commercial vehicles, as well as for enforcement applications. (See Enforcement and See Video)
Speed detection is an integral part of speed camera enforcement systems used to detect speed-related violations of traffic rules especially at accident hot spots. (See Speed Management) Regulation of speed is important at work zones where personnel are at increased risk of an accident. It is also a feature of active traffic management schemes on motorways. Some speed enforcement systems automatically link speed cameras to vehicle number-plate (Licence-plate) recognition for issuing enforcement notices. (See Traffic Management and Integrated Strategies) Speed detection can also be used as a safety measure at signalised intersections on fast arterial roads by using microprocessors to extend the green time at traffic signals when a vehicle is approaching at speed.
For measuring speed, the most common device is a radar meter or sensor which uses the Doppler principle. Specifically, the device measures the difference in the emitted and reflected frequency of a radar wave – which is proportional to the speed of the moving object. Other types of vehicle sensors can be adapted in pairs to measure speeds – such as ultrasonic sensors and magnetometers.
Journey time monitoring is related to speed monitoring. Vehicle journey times are significant sources of information for network performance monitoring and advising road users about travel delays in real-time. They are a measure of the level of service on offer. Some road authorities display point-to-point journey times on roadside VMS as a form of real-time information. Journey time data (historic and in real-time) is also a useful resource for journey planning and logistics support. (See Journey Time Monitoring)
Various methods are available to anonymously track vehicles on the network and enable network operators to determine average travel times, point-to-point demand and traffic flow conditions. For example, Automatic Toll Collection (ATC) systems can be used to determine the average travel time on highways between toll collection plazas or specially installed roadside readers. Infra-red (IR) tag-equipped vehicles are used as probes for monitoring traffic flow conditions – which are detected by transponder readers, installed along roadways. Aggregate data on average speeds and travel times can be compiled and this helps support incident and traffic management. To protect travellers’ privacy, these systems scramble the toll tag identifiers and only keep records of trips made by anonymous vehicles.
A number of other techniques are used to provide continuous, non-invasive, point-to-point tracking of individual vehicles to determine travel times and calculate average speeds. They include automatic number-plate recognition cameras (ANPR cameras) to identify vehicle licence plates. A new development is point-to-point monitoring of Bluetooth signatures emitted by equipment present in the vehicle. Bluetooth sensors have been used successfully for point-to-point average speed monitoring as a cheaper alternative to ANPR. Some road authorities use aggregated data (made anonymous) to display on VMS to provide drivers with expected journey times between key points on the network.
Environmental sensors are used in road network monitoring to detect adverse weather conditions such as icy or slippery conditions, high winds or precipitation (snow or rain) or the presence of fog/mist. This information can then be used by operators to alert drivers via variable message signs (VMS). It can also be used by highway maintenance personnel to optimise winter maintenance operations. (See Weather Monitoring)
Environmental sensors can be divided into six types:
Many manufacturers provide complete weather station systems that are capable of monitoring a wide range of environmental and surface conditions. The figure below shows one example of these weather stations.
(Figure 4.7 to be located here – to be supplied by the author)
Weather stations typically include the following types of sensors and capabilities:
Road condition sensors: A critical component of any road weather information system (or RWIS) is a set of road condition sensors that measure surface temperature and moisture, and detect the presence and thickness of snow and ice. Road condition sensors can be embedded in the pavements. They can also be non-intrusive – mounted to side or above the road surface. Non-intrusive road condition sensors typically measure the emitted infrared radiation from the road surface.
Visibility sensors: These sensors are designed to measure visibility along a road section. They typically use the principle of “forward scattering” or diffraction of light to detect changes in visibility resulting from inclement weather conditions such as fog, haze, and smoke. The sensors need to be carefully sited because they can only provide spot measures at a specific location. For example, fog detectors need to be sited as near as possible to the source where mist or fog forms first.
Thermal mapping: Given that temperatures can vary significantly along a roadway segment, thermal (temperature) mapping sensors are typically a critical component of an effective ice detection system. Thermal mapping provides road operators with information on road-surface temperatures to inform decision making on the need to set-up warning messages on VMS or to deploy snow clearance, road salting and gritting services. Examples of thermal imaging sensors include thermal imaging cameras/ video and infrared thermography.
Wind speed sensors: These are an essential component of an environmental sensing station and are installed at high and exposed bridges and windy locations on the road network. They typically measure surface wind speed and direction and can be used to provide warnings to vehicles towing trailers and high-sided vehicles. For safety reasons it is sometimes necessary to close the road in high winds.
Mobile reports can be divided into two categories:
In many cases, reports of incidents made by citizens and the police can provide significant road network monitoring information – and at a very low cost compared to other surveillance technologies. Mobile reports do not provide a continuous stream of condition data provided by other surveillance technologies, but they so provide event information at unpredictable intervals that are very useful for traffic management purposes. In particular, mobile reports are very effective for incident detection.
A number of different mobile reporting methods are used in road network operations.
Cell phones are a very effective tool for incident detection. Many regions have established an incident reporting hotline to encourage citizens to report traffic incidents. This has the advantage of low start-up costs.
The widespread use of cell phones can provide useful traffic information. Triangulation techniques can determine a vehicle’s position by measuring signals from an on-board cellular phone within the vehicle. To enable this, the cell phone needs to be communicating with more than one cell-phone cell – preferably three or more for accuracy – so that triangulation can take place. Each phone is typically identified by its electronic serial number. This concept was first tested in the Washington D.C. area in the mid 1990s. This concept is different from GPS-based AVI systems in which the GPS unit on the phone determines the location, which is then communicated from the phone to a central processing system.
Emergency Roadside Telephones (ERTs) were regularly provided prior to mobile telephones becoming widely available. ERTs still provide a valuable service where there is a low ownership of mobile telephones or a mobile-phone black spot. They provide an accurate location to the operator of where a caller is located and enable stranded motorists to call for help. More generally, they allow travellers to report incidents such as accidents or stray animals on the carriageway.
To use a call box, the motorist just needs to lift the receiver or press a key to request the services of the police or emergency services. The caller is automatically connected to a control room operator.
Advanced types of ERTs provide background noise cancellation against traffic noise, and a simple question and answer facility based around «yes» and «no» keys for the profoundly deaf and foreign travellers. The Operator has a formal list of questions that they can ask in sequence by typing in the questions. The questions appear on a small screen at the ERT and the user answers using the yes and no keys. The option to select different languages is a great advantage near ports and border crossings where there is a high percentage of foreign visitors. They also have a call-back facility that enables the operator to call the stranded motorist, with a beacon and ring tone to attract attention.
Typically, the phones are located on the side of the freeway, and are spaced at distances ranging from 0.25 miles to 0.50 miles apart. On all-purpose dual carriageway arterial roads, freeways and motorways they need to be located in pairs on either side of the road to avoid travellers being tempted to cross the road to use one.
(Figure 4.5 Call Box – Image to be provided by Barry Moore)
These are teams of trained officers who are responsible for covering a given segment of the freeway. Mobile patrols have a central part to play in road network operations, spotting debris on the road, dealing with incidents and the general public. A freeway service patrol vehicle [Figure 4.6] is typically equipped to be able to help stranded motorists and, where possible, to clear an incident site. Mobile patrols are capable not only of responding to incidents, but in some cases to perform the entire incident management process (from detection to clear-up).
Technology, in the form of secure mobile communications and hand-held tablets, provides support. TETRA mobile radio communications offer digital transmission capability whilst maintaining the advantages of a Private Mobile Radio (PMR) system. In future service patrols may have command and control capability to direct and manage the deployment of on-road resources – and the potential to set VMS and signals on location, remotely from the road side.
Figure 4.6 A Freeway Service Patrol Vehicle
A relatively new technique for collecting traffic-related information based on mobile reports is crowdsourcing – using social networks such as Facebook and Twitter. Crowdsourcing is the process of obtaining information online that is provided by a crowd of people. This method has become feasible in recent years because of the significant developments in positioning and communications technologies that are linked to mobile phones which have internet connectivity. In road transport, crowdsourcing concept can be used to collect vital travel-related information in collaboration with members of a community. One of the most famous and successful of these crowd-sourcing applications is WAZE (https://www.waze.com/) – one of the world's largest community-based traffic and navigation apps. Users of WAZE share real-time traffic information, allowing members of the on-line community to save time and fuel while travelling.
Vehicles are used to report journey times and detect traffic incidents – monitoring their progress in time and space. This can be done by either using automatic vehicle location systems or by tracking the progress of identified vehicles between known fixed points on the network. The location of the vehicle in time and space is communicated to a central computer where data from different sources is fused to determine the status of traffic flow over the transport system.
Vehicle probes can provide very useful information that other detection techniques cannot – including information on link travel times, average speeds, and origin-destination information.
Different technologies are available. These include:
Vehicle probe methods give more reliable but less dense data than crowd-sourcing, which may provide better geographical coverage. Vehicle probes are often deployed by road network operators in collaboration with the owners of vehicle fleets that regularly travel the network.
CCTV cameras play an important part in road network management. They are installed at sensitive locations on the network to support traffic management, where congestion and traffic queues are frequent and at other locations where there is an increased risk of accidents and traffic incidents. When used for traffic surveillance they can either have a fixed field of view – for example, when used to monitor traffic and provide alerts – or be equipped with a pan, tilt and zoom (PTZ) capability to allow operators to have a wider field of view.
Fixed field of view cameras are generally used for monitoring motorway sections where hard shoulder running is permitted.
Pan, Tilt Zoom (PTZ) cameras are commonly used for:
Either fixed or PTZ cameras can be used:
Control room operators depend on the CCTV camera images – displayed either on their work-stations or large-scale on a “video wall”. CCTV camera images are an important means of traffic surveillance that complements other traffic control measures. Operators rely on images from CCTV cameras to detect and monitor traffic incidents and assess the number of running lanes affected. From this it may be possible to estimate the likely duration of a traffic incident based on previous experience and traffic modelling techniques. Video image processing is used to alert control room operators to stationary vehicles and other unusual events. Operators often wish to see a sequence of images from successive CCTV cameras, in the form of a “video tour” (See Traffic Control).
Pan, Tilt and Zoom (PTZ) Closed Circuit TV Camera (Image courtesy of the IBI Group)
Video image processing (VIP) identifies vehicles and their associated traffic flow parameters by analysing imagery supplied from CCTV cameras which normally have a fixed field of view. The addition of VIP significantly improves the usefulness of CCTV, particularly where there are a large number of cameras installed, which an operator cannot view at the same time. VIP also provides the means for alerting operators to a traffic incident.
Analogue CCTV images are digitised and then passed through a series of algorithms that identify changes in the image background. In modern digital cameras the video image is already in a digital form – ready for processing. A VIP system consists of a video camera (a digitiser in the case of analogue cameras) and a microprocessor for processing the digital-image – and software to interpret the image content and extract detection information from it.
With digital processing CCTV provides an above-ground alternative to inductive loops or other means of vehicle detection. One big advantage of VIP systems is their ability to provide detection over a number of lanes and in multiple zones within the lane – providing wide area detection. The user can easily modify the detection zones, within seconds, through the graphical interface – without the need to close traffic lanes and dig-up the pavement. Poor lighting, shadows, and bad weather can negatively affect the performance of VIP systems. Evaluation studies in Oakland County, Michigan indicate that modern VIP systems yield excellent performance with a detection accuracy of over 96% under all weather conditions.
VIP systems can be combined with CCTV systems to provide an excellent detection tool, particularly for incident detection and verification purposes. When an incident occurs, the user can switch from the VIP mode to the standard CCTV mode, and then verify the occurrence of the incident via pan/tilt/zoom controls.
An effective interface with users is an essential part of many ITS applications. Users include control centre operators, the police and emergency services, road users and travellers. Many technologies support the dissemination of pre-trip and en-route information. To make traveller information available, historical and current traffic data and status of the network needs to be monitored and processed and put in a format which travellers can easily access (See Travel Information Systems).
Pre-trip traffic information provides travellers with information before they start their journeys. Examples of pre-trip traveller information include information on current or expected traffic conditions, current and expected weather conditions, and information on public transport schedules and fares. It is intended to help travellers to make informed route/mode/time of departure decisions (See Pre-trip Information).
En-route traffic information provides travellers with information while they are travelling. En-route traffic information includes many of the same elements provided for pre-trip planning – but updated in real-time – such as information on current and expected traffic and weather conditions, information on incidents and suggested diversion routes.
ITS uses many traffic information dissemination platforms to keep people informed about current as well as expected travel conditions. These include Dynamic Message Signs (DMS), Highway Advisory Radio (HAR), cable TV, traveller information websites and the Internet, dedicated phone systems, cellular telephone applications – and in-vehicle display. Information dissemination devices can be classified as:
With the proliferation of portable and mobile computing devices – such as smart phones and tablets – this three-way distinction is less clear now than it used to be. These are capable of accessing the Internet while the traveller is en-route – and there may be concerns about driver distraction and regulations against their use in certain circumstances (See Human Factors).
Dynamic Message Signs are also referred to as Variable Message Signs and Changeable Message Signs. In this website the following terminology is used:
A DMS may be either a Variable Message Sign (VMS) or Changeable Message Signs (CMS) where:
DMS are among the most common types of devices for information provision. They can either be fixed or portable as shown below. They can be text-based, graphics based or a combination of the two (See Traffic Management)
Figure 4.12 Fixed Dynamic Message Signs
Figure 4.13 Portable Dynamic Message Signs
DMS can be used to provide travellers with instructions such as closed lanes or recommended speeds and information on traffic and weather conditions, incident locations and expected delays, construction work, alternative routes and speed advisories. Different types of DMS can be light-reflecting, light-emitting, and hybrid according to the technology used. Light emitting diodes (LEDs) are generally the preferred option where there is a power supply (including solar options).
As the name suggests, these rely on an external source of light, such as the sun, headlights, or overhead lighting, to make them visible – by reflecting the light source. Different types of light-reflecting signs include rotating drum and reflective disk matrix signs. Rotating plank/drum signs are made of one to four multi-faced drums, each containing two to six fixed text messages or graphics. The main application of rotating plank/drum technology when it is incorporated into a fixed direction sign – is to provide variable instructions, that are identical in appearance to the fixed sign face, to show an alternative direction to a destination.
Reflective disk matrix signs comprise an array of permanently magnetised, pivoted indicators that are black on one side, and reflective white or yellow on the other. When a specific pixel is activated, an electric current flips the indicator from the black finish to the reflective yellow finish.
Reflective disk matrix signs were popular in 1970s for freeway management systems because they were less costly than light-emitting signs. Mechanical failure of some or the entire message is common (disk failure). As LED signs become less costly the older technology is falling out of use.
These generate their own light on or behind the viewing surface – either in monochrome or full colour. Light emitting diode (LED) and fibre-optic DMS are two examples:
LED has become the preferred technology. New versions of LED DMS provide a display known as a full matrix that can display graphics and images.
Hybrid DMS combine the characteristics of both light-reflecting and light-emitting DMSs. One of the best examples of hybrid DMSs is the reflective disks/fibre-optic or LED DMS. During weather conditions when light-reflecting DMS are not clearly visible, these hybrid systems can use light-emitting technologies such as fibre-optics or LED. When the sun is shining, the light sources are turned off. Solid state LEDs are more reliable than reflective disks since there is no risk of mechanical failure.
In-road markers or lane lights (also known as intelligent road studs) can be used to convey important messages to drivers, in addition to their most direct function of lighting the way at night. For example, in-road markers can be used to communicate the usage of a lane. Intelligent road studs have been used for signing the use of the hard shoulder during periods of heavy congestion, hazard warnings and operation of part-time bus lanes
These devices are typically located inside the vehicle and, similar to DMS, are designed to provide information to drivers while en-route. In-vehicle information devices can provide information by either audio or visual means. Examples of auditory in-vehicle information devices include highway advisory radio (HAR), cellular phone hotlines and commercial radio. Examples of visual in-vehicle devices include video display devices and head-up displays (which drivers can read without altering their normal viewing position
Highway advisory radio (HAR) provides another means for disseminating information to drivers while en-route. Typically, information is provided through an AM receiver. Drivers are informed about the existence of an HAR signal by signs which are typically installed upstream of the signal, advising drivers to tune in to a specific frequency (typically either 530 kHz or 1610 kHz) (See Radio).
HAR can be used to provide travellers with information similar to that provided by VMS. One advantage of HAR compared to VMS is that it is less distracting – since information is provided through a different sensory channel (audio) which reduces visual information overload. More complex messages are also possible with HAR compared to DMS. The disadvantage is that users have to tune to the frequency themselves.
Another way of providing information to drivers en-route, – which has increased in popularity with the widespread use of cellular phones – involves establishing a “hotline” phone system for traffic information that drivers can call from their cell phones while en-route (such as the 511 system in the US). The phone systems typically include a touch-tone menu that allows callers to receive route-specific traffic information – this gives the driver control over the type of information received.
Commercial radio is another means of providing en-route traveller information. The primary disadvantage of commercial radio is the accuracy and timeliness of the information. Typically, information is broadcast only when normal scheduling permits – and in many cases, this may be inappropriate since an incident might have been cleared by the time normal scheduling permits broadcasting.
A recent approach to disseminating traffic information en-route involves the use of dashboard displays, video and head-up display terminals. Close attention to the design of the Human-Machine Interface is needed to minimise driver distraction (See Human Factors).
These technologies are widely used for pre-trip and off-roadway information dissemination. They include cable TV, phone systems, the internet, pagers, smart phones and tablet computers. Many metropolitan areas around the globe now have websites dedicated to traveller information. These systems provide travellers with a wealth of travel-related information, including current travel conditions, alerts, and other timely information. A traffic map showing current speeds, locations of any incidents or construction zones typically form a central part of these websites. Among the technologies used for off-road roadway information dissemination are dynamic public information displays and kiosks – and mobile devices.
Large shopping malls and motorways often have dynamic information displays and kiosks where real-time travel conditions may be provided. This is also true of many motorway rest areas. These displays and kiosks were very helpful before widespread public take-up of mobile computing devices and smart phones. With the advent of these technologies, public information displays and kiosks have played a secondary role in information dissemination. They are still available at many sites and are useful for those sectors of the population who do not have access to mobile computing and smart phones.
The high market penetration of smart phones, tablet computers and personal navigation devices has provided the transport industry with an invaluable tool for disseminating travel information. The unique advantage of these nomadic and mobile devices is that they make travel information available to travellers on a continuous and uninterrupted basis.
Many navigational devices and services include real-time information about the transport network conditions. This is demonstrated by services such as Google maps and navigation – as well as by GPS navigation devices that can receive real-time traffic condition information. Crowd-sourcing is also being used to collect and disseminate travel information.
Telecommunications are an essential part of Road Network Operations and Intelligent Transport Systems. Over the past 40 years they have been developed piecemeal to support network operations – for example by linking control centres with roadside devices such as telephones, CCTV cameras, Variable Message Signs (VMS) and traffic signals. Today digital communications dominate the transmission of voice, video and data signals. Digital technology is inherently more reliable, flexible and manageable compared with previous generations of communications technology. Digital communications enable the development and operation of modern traffic management technology and the latest ITS applications – including connected vehicles and Active Traffic Management. CCTV is used increasingly and digital transmission of video images is possible over distances without the image being degraded.
Telecommunications networks resemble the nervous system in a human body. Specifically, the communications networks tie the different components of ITS together, allowing for a truly integrated system. For example, they provide a data link from the field devices (detection technologies, Dynamic Message Signs, signal controllers) to traffic operations centres – where the collected data is fused, analysed and acted upon. This is illustrated in the diagram below. Telecommunications are also needed to carry instructions and commands from control centres back to field devices for traffic control purposes. They are also the means for infrastructure operators (controllers) relaying information to travellers and stakeholders.
National Roads Transmission Network for England (Courtesy of Highways England. In this diagram MIDAS means Motorway Incident Detection Alert System.)
An ITS system will not function without an appropriately designed communications network that has adequate bandwidth and is capable of delivering an adequate level of service (in terms of message delivery, latency and drop-out rates). Decisions on the appropriate communication technology, the appropriate network topology and other communications design issues have to be made carefully. This is because the cost of the communication network typically constitutes a major component of the cost of a specific ITS system. In some cases, where a cable and transmission equipment infrastructure needs to be installed, it can be up to 50%.
There are a number of options for ITS professionals. Traffic operators need to decide how best to meet telecommunication needs and what they are capable of doing. Broadly speaking, the technologies can be divided into wired communications and wireless communications. The choice for roadside installations is often a trade-off between cost and functional capability.
The telecommunications network to support ITS needs to be carefully designed. A common architecture for such networks is known as a hierarchical or layered architecture, which exhibits many similarities to the hierarchical system of road networks themselves. Specifically, telecommunications networks may be regarded as consisting of four layers:
Using highways as an analogy for telecommunications, the backbone layer is similar to the inter-state / inter-urban strategic roads. It enables moving (hauling) large amounts of data between a limited number of fixed distribution points. As with road networks, the different layers of a communication network are interconnected. Fibre optics cables are commonly used for this layer.
The function of the backhaul layer is to move (haul) large amounts of data (which still requires large bandwidth) from the backbone network to the Traffic Control Centre. It is often off the highway/road network – and can be provided by a service provider such as a telecommunications company (TelCo).
The distribution layer resembles the system of arterial roads in a road network. This layer typically does not handle large volumes of data. Its main purpose is to provide multiple points of presence to enhance accessibility.
Finally, the access layer resembles a residential or local street network or the lead/cable which connects the TV to the aerial socket – that provides local cabling to access the different devices on the network.
Another option for transport agencies is to lease wired communications services from a telecommunications company. In earlier years of ITS, some ITS applications (urban control systems) used leased telephone lines – their limitation is the very low bandwidth provided by telephone lines. Today it is becoming increasingly cost effective to use WiFi to replace leased telephone circuits, particularly in urban areas – or as an alternative to costly new cable networks for inter-urban roads when bandwidth requirements are modest.
More recently, new technologies have been developed to help improve the speed of communications on local telephone networks. In particular, Digital subscriber line (DSL) – which uses higher frequency bands for data – can offer speeds of up to 40 Mbits/second. Asymmetric Digital Subscriber Line (ADSL) is a type of digital subscriber line (DSL) technology that enables faster data transmission over copper telephone lines. Another technology is cable internet which uses cable television networks in much the same way as DSL uses telephone lines. Cable Internet could have speeds of up to 400 Mbits/second – and so can support most ITS applications that have demanding bandwidth requirements.
It is often more cost effective to lease dark fibres from a telecommunications operator or buy-in a service rather than install a dedicated system. Leased Communication Systems in ITS are widely used for urban traffic control systems and to provide the backhaul for connecting TMCs to the field communications on a motorway.There are two reasons for this:
Leased communications also provides a means for satisfying the communications needs of rural ITS applications where the installation of new communication lines may be too expensive.
Highways England (a Government owned company) established a public-private partnership to upgrade, operate, and maintain the communications systems that link the roadway communication devices (emergency telephones, CCTV, etc.) along the motorways and other strategic roads in England. A telecommunications consortium was selected for a 10 year project.
The consortium has end-to-end responsibility for voice, data and video transmission services that link the Highways Agency’s roadside devices to the control offices. The roadside devices and control centre applications themselves remain with the Agency. The consortium is responsible for monitoring the performance of the transmission services, for providing a resilient and reliable service and for providing additional local connections to support additional roadside devices.
Wired communications use fibre optic and copper cables to connect roadside equipment to control centres. Typically these cables run in ducts along the motorway or roadway with the necessary data transmission equipment housed in roadside cabinets. The control centres themselves are in strategically located buildings with cable connections to the main network.
Wired communications include a wide range of technologies that vary in performance, cost and bandwidth – meaning the volume of data that they are capable of communicating is variable. At one end of the spectrum there is fibre optic technology that provides the highest bandwidth of any communications system existing today. At the other end are the old-fashioned telephone lines with limited bandwidth for data transfer.
A fibre optics cable is a communications medium for light waves to carry a signal that transfers information from one point to another. The cable itself is very thin (slightly thicker than a human hair). For operations, an optical transmitter is needed at one end of the cable, and a receiver at the other – to convert electrical signals into light signals and back again at the receiving end.
Current fibre optics technology is capable of transmitting about 1.5 Gbits of information per second.
Another advantage of fibre optics communication is that it is not susceptible to magnetic interference or electrical resistance, since it uses light waves. On the downside, fibre optics communications are relatively expensive, although their widespread use nowadays has made them more affordable. A large portion of the cost of fibre optics technology relates to purchase of the -of-way, the termination equipment (converting electrical pulses to light and back again) – and the trenching needed.
A number of highway transport agencies have entered into an agreement with a telecommunications company:
Fibre optic cable is commonly used in ITS for applications where there large amounts of data transmitted. A good example is the connection between a Transportation Management Centre (TMC) and field devices such as video cameras. There is emerging interest in taking fibre cables direct to the end-devices – leading to roadside equipment now being specified with an optical fibre input or connector-socket. Fibre optic cables are expensive and challenging to fix when damaged.
Copper cabling is good for voice and data transmission – but increasingly cable systems need to transport high bandwidth signals associated with CCTV images and other video. Fibre optics are rapidly replacing copper for ‘main line’ telecommunications – but distribution within buildings and over the last mile often relies on copper coaxial cable. Copper cabling requires the use of line amplifiers to cover distance – with an increased risk of noise on the high bandwidth signals. With the spread of digital signalling and ADSL (see below) existing copper cables are having a new lease of life to provide the distribution and access layers.
Twisted wire pair (TWP) is amongst the most common communications media for ITS applications. It is made of two insulated copper conductors twisted together to cancel out electromagnetic interference. Recent advances have allowed the use of Ethernet over TWP in a number of ITS applications.
Twisted wire pairs are the most commonly used option for ITS communications for the access and distribution layers – especially since recent advancements in ADSL technology allows the use of Ethernet over TWP. This has also opened opportunities for the utilisation of legacy TWP infrastructure. ADSL is now widely used – following the practice of Telecommunications Companies – to make best use of their extensive existing copper cable networks.
Ethernet cable is used to create Local Area Networks (LAN) providing a physical data network – connecting devices together within a control centre. It carries data using the Ethernet protocol which is almost exclusively used for ICT applications in buildings/offices. The current most commonly used industry standard is Category 5 (CAT5), which contains four pairs of copper wire, and supports speeds of up to 100 Mbits/second. Newer standards are now allowing for faster speeds up to 1000 Mbits/second. CAT5 cable is limited to a maximum recommended length of only 328 feet.
An interesting development for ITS in recent years is the concept of Power over Ethernet (PoE), which allows a single cable to provide both the data connection as well as electrical power to ITS field devices. PoE allows for longer cable lengths.
Apart from the need for an Ethernet network within the TMC, Ethernet cables are commonly used in ITS to form the access layer to connect a field device (such as a CCTV camera) to a network or to an Internet access point. In this case the cables are there primarily as local device interconnects.
Advances in digital technology over the past two or three decades have made wireless communications an attractive option for road-based ITS in situations, such as control of VMS, car park counters, traffic signal communications, remote monitoring and CCTV. Specialised ITS applications also rely on a variety of wireless radio services for communication – principally:
Standardisation of Wireless Communications for ITS in Europe
In Europe efforts to standardise wireless communications for ITS are directed towards the creation of a continuous long-range / medium-range continuous air interface using a variety of communication media, including cellular, 5 GHz, 63 GHz microwave and infra-red links. The initiative is known as CALM – which stands for Continuous Air-interface Long and Medium (CALM). CALM will provide the communications platform for a range of applications, including vehicle safety and information, as well as entertainment for driver and passengers.
Some of the more common wireless communications media that are used for ITS include:
Point-to-point microwave communication uses ground-based transmitters and receivers resembling satellite dishes to provided dedicated backhaul links where landlines would impractical or prohibitively expenses to connect roadside networks to a control center. They are usually in the low-gigahertz range and limited to line of sight. Repeater stations can be spaced at approximately 48 km intervals to cover greater distances.
Wi-Fi has become a very popular technology for the exchange of data wirelessly using radio waves over a computer network. Wi-Fi can support non-critical ITS applications because it avoids delay – but does not have bandwidth guarantees. Wi-Fi operates using unlicensed frequencies – so are more susceptible to interference. The technology has potential for use in ITS as a means for connecting field devices to a Traffic Control Centre – for example, where a wired communications solution would be too expensive. In this case, a secure Wi-Fi connection, such as the wifi-mesh network shown in the figure below would need to be provided. This shows a multipoint to multipoint WiFi Mesh network suitable for VMS, car park counters, traffic signals, remote monitoring and non-enforcement CCTV.
Wi-Fi is based on the Institute of Electrical and Electronics Engineers’ (IEEE) (IEEE) Standard 802.11. It is designed to provide local network access over relatively short distances (between 50 – 100 meters) with speeds of up to 54 Mbits/second.
Figure 6 Diagram of a wifi-mesh network suitable for highway data transmission
(Figure courtesy of Barry Moore)
Bluetooth technology also supports data exchange over short distances. It uses short-wavelength ultra-high frequency (UHF) radio waves. Bluetooth technologies are used in many different applications such as smart phones, headsets, tablets and laptop computers. Recently, there has been increased interest in building on the presence, on-board vehicles, of Bluetooth devices in “discoverable” modes, to track and monitor traffic. These applications use roadside Bluetooth detectors to discover Bluetooth devices on-board the vehicles and detect their unique identifier. By tracking the same identifier through different location points, important traffic parameters can be determined such as travel time, speed, vehicle origin and destination.
Another group of communications technologies widely used in ITS is dedicated short-range communications (DSRC). DSRC was developed specifically for vehicular communications and is likely to witness a dramatic increase in use with the introduction of Connected Vehicle technologies. The technologies are used in a number of ITS applications including:
In the USA, DSRC generally refers to communications on a dedicated 5.9GHz frequency band reserved specifically for Wireless Access in Vehicular Environment (WAVE) protocols – defined in the IEEE 1609 standard and its subsidiary parts. These protocols are based on the widely-used IEEE 802.11 standard for Wi-Fi wireless networking.
Several DSRC technologies are used in transportation. These include:
Passive tags do not have an internal power supply. Instead, they use the very small electrical current induced in the antenna by the incoming radio frequency signal, to transmit a response. For this reason, the antenna has to be designed not only to collect power from the incoming signal, but also to transmit the outbound backscatter signal. The main advantage of passive microwave tags is that they can be quite small and have an unlimited life. Passive microwave was used in ITS for early types of electronic toll collection systems. Innovations in their use continue.
Active tags have their own internal power source which can generate the outgoing signal. Compared to passive tags, they may have a longer range and can store additional information sent by the transceiver. Active microwave is employed in many electronic toll collection systems. More expensive on-board units have batteries which need replacing.
Infra-red DSRC uses infra-red technology, as opposed to radio spectrum or microwave, for short-range communications. Infra-red DSRC can be used in ITS where it is difficult to secure a frequency spectrum license. The technology is also appropriate when the weather is generally rainy – but not foggy. Infra-red DSRC is less susceptible to security intercepts.
Bluetooth is a wireless technology designed to allow data exchange over short distances (a maximum of about 10 meters). Most cell phones on the market today have Bluetooth technology. They also have Wi-Fi wireless technology, which uses radio waves for connections for distances to a Wi-Fi base station of up to 90 meters. In recent years, several automotive manufacturers have been embedding Bluetooth technology into their vehicles to allow drivers to connect their phones or music devices to in-vehicle audio systems.
When activated, Bluetooth and Wi-Fi transceivers continuously broadcast “discovery” messages to allow other devices to find and connect with them. The discovery messages include a unique identifier that can be used for vehicle detection and tracking. Essentially, all that is needed is a Bluetooth or Wi-Fi sensor installed close to the roadway. These sensors record the time at which a a vehicle equipped with an on-board Bluetooth or Wi-Fi device drives past them. By utilising the unique identifiers recorded at successive monitoring points, information on travel times along a road segment – or the pattern of Origin-Destination flows through a network – can be derived.
The use of Bluetooth or Wi-Fi is ideal for crowd sourcing but the results have to be calibrated as:
not all vehicles report an identifier – since some will not be equipped with the technology or the equipment may be turned off – leading, in both cases, to no count being registered
or a single vehicle may have several active devices – leading to multiple counts.
When using this vehicle sampling technique a key challenge is to ensure that a sufficiently high proportion of vehicles are equipped with Bluetooth and Wi-Fi devices. In urban areas, this may not be a major concern, but in other regions low market penetration may limit the application of these detection technologies.
Communications over a wide area are often required in Network Operations – particularly in rural areas where the options for voice and data communications and the transmission of CCTV images are more limited.
WiMax stands for Worldwide Interoperability for Microwave Access. WiMax is designed to provide much higher bandwidth, compared to Wi-Fi, and at a much extended range. Recent years have seen increased interest from the ITS industry in integrating WiMax and Wi-Fi as an alternative communications medium to wired communications.
Under ideal conditions, WiMax could have a range of more than 40 kilometres, and offer speeds of up to 70 Mbits/seconds. It implements the IEEE 802.16 Standard, with newer standards designed for speeds of up to 1 Gbits/second. A typical WiMax network would consist of a base station connected to several client radios (Customer Premise Equipment or CPE).
Cellular networks were established primarily for voice communications, but there is steadily growing increased interest in their use for data communications as well. Two voice communication cellular technologies have evolved in this way:
Global System for Mobiles (GSM)
Code Division Multiple Access (CDMA)
They differ in the way they transfer data. GSM divides the frequency band into multiple channels for use by different users. CDMA digitises calls and unpacks them at the back end. Both GSM and CDMA have been refined and enhanced over the years to allow for increased speed. For example GPRS (for packet data communications) uses the GSM cellular network at speeds suitable for transmitting commands to VMS and car park counters.
The latest cellular data technology is Long Term Evolution (LTE) (also known as 4G LTE). Unlike GSM and CDMA, LTE is designed primarily for data communications, with voice as an override. It offers high bandwidth, low latency, and supports full data rates while travelling at high speeds (a feature which is important in the ITS environment with fast-moving vehicles). Cellular data communications can be used in ITS where wireline communications are not available or are cost-prohibitive.
Digital Radio Data (DRT) refers to the practice of transmitting digitised and compressed data over FM radio. This allows small amounts of digital information to be embedded in conventional FM radio broadcasts. A good example of a DRT application in ITS is the Radio Data System-Traffic Message Channel (RDS-TMC), where digitally encoded traffic information is made available for in-vehicle navigation devices. RDS-TMC is an early form of digital data transmission. It was developed in Europe to exploit the Radio Data System used by some broadcasting authorities. Travel information is transmitted digitally over FM radio frequencies – and a decoder, built into the car radio or navigation device, interprets the digital code for text or graphic display.
Spread spectrum radio is a radio network that has a “line-of-sight” requirement (unobstructed line of path between a subject and an object). In this network, one radio serves as the master and the other as slave. An example of the use of spread spectrum radio in ITS is the connection between a set of traffic controllers at signalised intersections and the Traffic Management Centre (TMC) needed for monitoring and signal timing purposes.
In some cases, it might not be possible to directly link the two radios because of distance or interference – in which case another radio (called a repeater) would need to be installed in-between the two radios. These networks are most commonly used to allow a number of traffic controllers to communicate with one another, or to communicate with a traffic operations centre. They can broadcast over the unlicensed frequencies of 900MHz, 2.4 GHz and 5.8 GHz. The 5.8 GHz frequency provides the highest bandwidth at about 54 Mbits/second, but is very susceptible to line-of-sight problems.
Whilst theoretically, spread spectrum radio can provide a communication range of up to 60 miles, in practice the range is much shorter because of line of sight attenuation or obstructions.
A number of traffic control strategies can be implemented in Road Network Operations in order to improve traffic flow, prevent congestion and enhance throughput. ITS software – supported by a wealth of real-time data enabling accurate estimates to be made of the status of the road network – is used to develop optimal management and control strategies that support network policy objectives. These will vary from one location to another, but commonly include maximising traffic throughput, minimising delays and congestion, maintaining road safety for all road-users – including safe crossings for pedestrians and cyclists – environmental targets (to reduce noise levels and/or air pollution) and bus/tram signal priority for some locations.
Control methods include:
Urban Traffic Control (UTC), with:
Motorway control systems, including:
Field controllers are needed to implement these strategies. They are the “brains” of the local system, and provide the means for accessing, monitoring and controlling field equipment (such as a ramp meter, a traffic signal, or a vehicle detector).
Computer software is needed to provide these functions. Some of the functions that an ITS system software may be required to provide include urban traffic control, traffic control on arterial roads and motorway control systems.
Urban Traffic Control refers to a package of technologies aimed at managing and controlling traffic flowing over urban networks – to minimise delay, maximise efficiency, improve safety and reduce emissions and fuel consumption. A large part of urban traffic control involves software to optimising signal plans at intersections to achieve these objectives. This requires extensive sensor networks to collect real-time traffic information – for example, loop detectors, closed-circuit TV cameras and video image processing, or non-intrusive traffic detectors. Based on the collected information, intelligent algorithms aim to optimise the signal plans. Different levels of control and sophistication are seen in urban traffic control systems (See Urban Traffic Control).
Several types of field controllers are available which respond to traffic demands to facilitate turning movements and allow time for cross-traffic. In the USA the Type 170 Controller was developed in the early 1970s by the California Department of Transportation. Its successor – Type 2070 – was introduced in 1992. More recent examples are the NEMA signal controllers and the Advanced Traffic Controller (ATC – 2005) – the most advanced controller in the USA.
Traffic signal controllers work on the basis of a timing cycle that is broken into “phases” – the order in which each traffic stream is given green time, whilst other traffic is held at red. A simple cross-road intersection may have just two phases: North/South, and East/West. A busy four-way intersection, with large volumes of turning traffic, might have up to eight phases – one phase for each of the four traffic directions and a phase for each of the turning movements.
In the United Kingdom, a relatively new controller called Microprocessor Optimised Vehicle Actuation (MOVA) was developed to overcome some of the limitations associated with traditional Vehicle Actuation (VA) control. A unique feature of MOVA is that it has two modes of operation – one for congested traffic conditions and one for uncongested or free-flow conditions. For free-flow conditions, the aim of MOVA is to deal with any queues that have accumulated during the red phase. An algorithm assesses the traffic loads from different intersection approaches and determines whether extending the green time is beneficial. If it is, the green phase is extended to let traffic through. This continues until the controller moves to a different phase. During congestion, MOVA’s operational objective changes to maximise the capacity or throughput for the intersection as a whole.
Motorway control systems focus on better management of motorway segments to enhance capacity and increase throughput. Over the years, several Decision Support Systems (DSS) have been proposed and developed to help this process. These DSS can provide recommendations to traffic operators on possible traffic control strategies – such as dynamic route guidance, ramp metering, changeable speed limits and optimal signal timing.
Automated motorway control systems (sometimes referred to as Active Traffic Management or ATM systems), use different concepts to achieve their goal – such as speed harmonisation, temporary shoulder usage, dynamic routing and signing, junction control and ramp metering (See Highway Traffic).
Active Traffic Management has been widely implemented in Europe, and is becoming a tool for managing congestion (both recurring and non-recurring), in the USA as well. The main technological components of ATM are similar to the UTC systems and include extensive sensing and monitoring systems, communications, controllers, and intelligent algorithms.
The benefits of Active Traffic Management systems include:
Urban Traffic Control (UTC) systems require traffic signals, signal controllers, ramp meters and dynamic message signs (Variable Message Signs – VMS) to control traffic. They also require:
Different approaches and measures are used for real-time traffic management and control in urban areas.
Computer signal control systems first appeared in the 1960s when computers were first used to coordinate the traffic signal controllers for a group of intersections – but without the benefit of today’s “feedback” of information from the field detectors to the computers. In this type of system (known as open-loop control) the traffic plans that are implemented are not responsive to actual traffic demand. Instead, plans are developed “off-line” using data from historical traffic counts – and implemented according to time-of-the-day and the day of the week.
This system is quite basic, but it still offers several advantages including:
The next level of sophistication is signal control systems where information from field traffic detectors is fed-back to the central computer. The computer uses the information on current traffic conditions to select the signal plan to be implemented (closed loop control). Plan selection is made according to one of the following methods.
Here, the system has access to a database (library) that stores a large number of different traffic patterns along with the “optimal” signal plans (developed off-line) for each traffic pattern. Based upon information received from the traffic detectors, the computer matches the observed traffic pattern to patterns stored in the library, to identify the most similar pattern. The “optimal” plan associated with the identified pattern is then implemented. This type of adaptive traffic control system is often referred to as a First Generation system. Its distinguishing feature is that the plans, while responsive to traffic conditions, are still developed off-line. First Generation systems work on the basis of current traffic data and do not generally have traffic prediction capabilities.
In this method, the “optimal” signal plan is computed and implemented in real-time. The optimal signal timings are computed in real-time using current data on traffic conditions obtained from detector information. This requires sufficient computational power to make the necessary computations on-line. It also needs enough data from the vehicle detectors to make the calculations. The systems that develop plans on-line are classified as either Second-Generation or Third-Generation systems. They typically have a much shorter plan update frequency compared to First-Generation systems, typically every 5 minutes for Second-Generation systems, and from 3 to 5 minutes for Third-Generation systems. In addition, some Third-Generation systems use forecasts of traffic conditions obtained from feeding the detector information into a short-term traffic-forecasting algorithm.
There are a number of examples of adaptive traffic control systems in use around the world. Amongst the most widely accepted algorithms are SCOOT, SCATS and RHODES.
SCOOT (Split, Cycle, Offset Optimisation Technique) is an adaptive traffic control system developed by the United Kingdom’s Transport Research Laboratory (TRL) in the early 1980s. SCOOT operates by attempting to minimise a performance index (PI) – typically, the sum of the average queue length and the number of stops across the controlled network. In order to do this, SCOOT modifies the length of the cycle, the amount of green time given to each signal phase (known as the time “splits”), and the offset time for each set of signals (the time difference between the cycle start times at adjacent signals). SCOOT computes these calculations in real-time in response to the information provided by vehicle detectors.
The operation of SCOOT is based upon Cyclic Flow Profiles (CFP). These are presented as histograms (graphical representations of user-specified ranges) that show the variation in traffic-flow over a cycle – which is measured by loops and detectors that are placed midblock on every significant link in the network. Using the CFPs, the offset optimiser calculates the queues at the stop-line. The optimal splits and cycle length are then computed.
Several additional features have been added to SCOOT to improve its effectiveness and flexibility, including the ability to:
The Sydney Co-ordinated Adaptive Traffic System (SCATS) was developed in the late 1970s by the Roads and Traffic Authority of New South Wales in Australia. For operation, SCATS only requires stop-line traffic detection, not the midblock traffic detection that is necessary for SCOOT. This simplifies installation since the majority of existing signal systems are equipped with sensors only at stop-lines. SCATS is a distributed intelligence, hierarchical system that optimises cycle length, phase intervals (splits), and offsets in response to detected volumes. For control, the network of signals is divided into a large number of smaller subsystems, each ranging from one to ten intersections. The subsystems run individually unless traffic conditions require the “marriage” – or the integration – of the individual subsystems.
Since 1991, the University of Arizona has been developing a real-time adaptive control system called RHODES, which stands for Real-time Hierarchical Distributed Effective System. RHODES is designed to take advantage of the natural stochastic (random) variations in traffic flow, to improve performance – a feature which is missing from systems such as SCOOT and SCATS.
The RHODES system consists of a three-level hierarchy that decomposes the traffic control problem into three components: network loading, network flow control and intersection control:
Level 3 is concerned with intersection control – determining the optimal time to change traffic signals for the next phase sequence and whether the current phase should be shortened or extended. The time frame for control level 3 is typically in the order of seconds and minutes.
Where there alternative routes available the problem of optimising traffic on the network can be tackled mathematically. For dynamic route guidance (DRG) the “objective function” (an equation expressing the operational function that needs to be maximised or minimised) – is the measure of the highway network’s performance that needs to be optimised. For example the objective might be to minimise the total travel time for all vehicles. The decision variables are the proportions of traffic that splits at each diversion point – to optimise network performance. The traffic-splits define how traffic should be distributed. The aim is to model traffic flow in the region and ensure that it is maintained at the nodes and along the links of the network, without congestion setting in. ITS software can then be used to solve the problem of optimising the objective function and recommending a routing strategy that will vary in real-time according to traffic conditions. Routing advice will be given in traffic broadcasts and on VMS, or with in-vehicle route guidance for those vehicles that are equipped.
Public transport priority (known as Transit Signal Priority or TSP in the USA) is a measure aimed at reducing delay for public transport vehicles (buses, trams, taxis) at signalised intersections by giving their movements preferential treatment. The methods for doing this can be divided into passive and active strategies. The basic difference is whether specialised sensors and detectors are used to detect approaching public transport vehicles. Without supporting technologies to specifically identify these type of vehicles, passive TSP technology simply improves conditions for all vehicles along a public transport corridor.
Active technologies detect an approaching bus or tram (this is typically accomplished by having a transmitter on the vehicle that communicates with a receiver or detector on the roadside signal controller). Different algorithms or strategies are available for active bus priority. Amongst the most common are:
Green Extension: this extends the green time if a bus or tram is detected, to allow the priority vehicle to pass – up to a certain pre-determined limit. This strategy only benefits a small portion of vehicles, but the reduction in delay for beneficiaries is significant (equal to the length of the whole red interval)
Early Green: shortens the green time for conflicting phases, by a pre-defined amount of time – for example when the bus arrives whilst the traffic light is in its red phase. Early green benefits a large percentage of buses, but the saving per vehicle is not as large as for Green Extension
Phase Rotation: under this strategy, the sequence of green time for different manoeuvres at the intersection is changed so that the priority vehicle is not held up. One common modification – that allows the vehicle to cross the opposing traffic stream – involves swapping a dedicated turn signal at the start of the cycle (the “leading” phase) to the end of the cycle (the “lagging” phase).
Actuated Transit Phase(s): involves establishing transit phases, which are only active when a bus/tram is present. In this case, a special transit signal face would display, for example, a letter “B” for Bus or “T” for Tram.
Phase Insertion: this allows the same phase to appear more than once during the same cycle in order to serve the transit vehicle.
An important function that ITS software can provide for Road Network Operations is the ability to detect incidents and abnormal conditions from automatic analysis of the real-time traffic surveillance data. The development of Automatic Incident Detection (AID) algorithms began in the 1970s, and since then many algorithms have been developed. They have had mixed success, primarily because of their relatively high false-alarm rates (measured as the ratio of the number of false detections and the total number of observations).
AID algorithms can be broadly divided into four groups based on the principle behind the algorithm’s operation. These groups are:
These are among the most commonly-used AID algorithms. They are based on the premise that the occurrence of an incident results in an increase in the density of traffic upstream and a decrease in traffic density downstream. The California Algorithm is one of the earliest comparative-type AID algorithms to be developed – and is often used for comparisons and bench-marking. Since the original California algorithm was first developed refinements have been made to its performance. At least 10 new algorithms have been produced, of which algorithms 7 and 8 are the most successful. The TSC 7 algorithm represents an attempt to reduce the false-alarm rate of the original algorithm. The TSC 8 algorithm test repeatedly for congestion effects upstream of an likely incident and monitors other traffic characteristics.
Catastrophe Theory derives its name from sudden changes that take place in one variable that is being monitored – whilst related variables, also being monitored, show smooth and continuous changes. For incident detection, catastrophe theory algorithms monitor the three fundamental variables of traffic flow – namely speed, flow and lane occupancy (density). When the algorithm detects a drastic drop in speed, without an immediate corresponding change in occupancy and flow, this is an indication that an incident has probably occurred. The McMaster algorithm developed at McMaster University in Canada is a good example of an algorithm based on this concept.
Statistical and time series methods are used to forecast future traffic states or conditions. By comparing real-time observed traffic data with data forecasts, unexpected changes are classified as incidents. An example of these algorithms is the Auto-Regressive Integrated Moving-Average (ARIMA) time series algorithm. ARIMA is used to provide short-term forecasts of traffic occupancies based upon observed data from three previous time intervals. The algorithm also computes the 95% confidence interval. If observations fall outside the 95% range as predicted by the model, an incident is assumed to have occurred.
Several Artificial Intelligence (AI) concepts have been applied to problems in transport engineering and planning. Automatic incident detection is one application. Detecting incidents is a good example of a group of problems known as pattern recognition or classification problems – for which AI theories are quite effective in solving. Amongst the AI concepts most often applied to the problem of incident detection are Artificial Neural Networks (ANNs). These use complex algorithms and multiple computer processors to recognise patterns and connections in the input data.
Over the last few years automotive manufacturers have been introducing sophisticated vehicle control technologies to improve safety, fuel efficiency and comfort level of drivers, amongst other things. These new technologies are sometimes called Advanced Driver Assistance Systems (ADAS). These systems use sensor technology, including automotive radar, that has been developed specifically for use in motor vehicles (See Warning and Control). They have a positive effect on safety and traffic management by helping drivers to maintain a safe speed and distance, keep within the running lane and avoid unsafe overtaking manoeuvres. Benefits can be further magnified if individual vehicles communicate continuously with each other or with the road infrastructure – so-called ‘connected’ vehicles (See Connected Vehicles).
Examples of longitudinal vehicle control are Adaptive Cruise Control (ACC) and Co-operative Adaptive Cruise Control (CACC). ACC is designed so that a car automatically maintains a safe distance from the vehicle ahead in terms of distance or time headway, as programmed by the driver. The driver specifies the maximum speed (as with normal cruise control) and the follow distance. An on-board radar sensor locks onto the vehicle ahead and the vehicle control system maintains the specified distance. ACC is often accompanied with a forward collision warning system that alerts the driver in case of an obstruction hazard ahead. It may even start to apply the brakes if the driver fails to do so.
Research is taking place that combines ACC with inter-communications between vehicles.. With communications added, ACC becomes Co-operative Adaptive Cruise Control (CACC). Communications allow the front vehicle’s rate of acceleration or deceleration to be communicated in real-time to the vehicle following (several times per second). The real advantage of CACC is to reduce delay in the response of the vehicle behind.
Some high-end new cars on the market now include lane departure warning systems and lane-keeping support systems. These keep track of the vehicle’s position relative to the running lane. They use a suite of sensors such as video sensors mounted behind the windshield, laser sensors on the front of the vehicle, and/or infrared sensors under the vehicle. Warning systems only sound if the vehicle starts to deviate from the lane, whereas lane-keeping support systems may take remedial action to return the vehicle to a safe position within the lane.
By combining technologies, the next evolution in vehicle control systems is autonomous or self-driving vehicles.
The US National Highway Traffic Safety Administration (NHTSA) has defined five levels of automation to describe systems with varying degrees of autonomyin the following way:
The Google car is an example of what is in development and on trial in California. youtube (See Video)
Digital mobile telecommunications are having a profound effect on the operating environment for ITS by enabling Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) communications. The combination of the two is sometimes referred to as V2X communications – meaning networked wireless communications between vehicles, the infrastructure (roadside units and traffic control centres) and passengers’ personal communications devices. A vehicle can broadcast data describing its position, movements and manoeuvres – and share this with other vehicles to prevent collisions, and with the infrastructure to optimise traffic control.
The ability to send and receive this data enables intelligent vehicle systems to integrate information from navigation systems with data from on-board sensors and information received from the infrastructure. This provides vehicle systems with an awareness of its immediate surroundings, including areas which may not be visible to the driver – which can be used to assist the driver to drive more safely. If the vehicle systems anticipate an accident they can, as a minimum, prepare safety systems and, perhaps, intervene to prevent an accident.
The technologies needed to implement a connected and Cooperative Vehicles (CV) environment fall into four separate components:
The OBE are:
Some of the vehicle-based information can be obtained from GPS or other similar sensors (for example location, speed, and direction), whereas other information (for example acceleration, instantaneous fuel consumption, anti-lock brakes activation, wiper status) may be obtained from vehicle engine scanning tools and other systems monitoring the vehicle’s different subsystems.
Connected vehicles are instrumented with a wide range of sensor technologies to enable applications aimed at improving safety and efficiency – including:
Roadside units and equipment are infrastructure systems that communicate with vehicles and collect data from the vehicle. Roadside equipment can support infrastructure-based applications – or applications involving co-operation between vehicles and the infrastructure (such as intersection collision avoidance systems, and eco-signals which inform approaching vehicles about the remaining green-light time to enable drivers to adjust their speed). Roadside equipment also supports remote applications by communicating information collected from the vehicles to a central location for processing. They also may help support the security and integrity of cooperative vehicle systems.
The communications network is the infrastructure needed to provide connectivity between vehicles (V2V), between vehicles and the infrastructure (V2I), and between roadside equipment and other parts of the system (V2X). Wireless communications are required for V2V and V2I communications, whereas roadside equipment may use wireless or wired networks.
The Connected Vehicles Initiative – USA
In the USA, the focus has been on using Dedicated Short-Range Communications (DSRC) for cooperative vehicle systems. Similar to Wi-Fi, DSRC is an open-source protocol for wireless communication. However, the big difference is that DSRC is intended for highly secure and high-speed communications – features that are critical for safety applications. DSRC has the following beneficial features:
low latency (as low as 0.02 seconds)
robustness in the face of interference
dedicated bandwidth protection (depending on bandwidth allocations in the country concerned)
In the USA, in 2004, the Federal Communications Commission, dedicated 75 MHz of bandwidth at 5.9 GHz, to be used for the Cooperative Vehicles initiative.
The rapid progress in mobile telecommunications means that the connected vehicle is no longer a research concept but a reality. Applications fall into four different, but not necessarily separate, categories:
connected vehicle safety applications – examples include driver advisories, driver warnings, and vehicle and/or infrastructure controls (See Driver Support);
connected vehicle mobility applications that use real-time data. The data are transmitted to vehicles wirelessly and are used by information service providers to broadcast current traffic conditions for satellite navigation systems. Data obtained from connected vehicles also has value for network management activities and for traffic engineers to optimise the performance of the transport system (See Probe Vehicle Measurements);
connected vehicle environmental applications that use real-time data from vehicles to support the development, operation, and use of "green" transport applications (See Smart Network Operations);
commercial applications that enhance the way business is conducted and open up new market areas – such as location-based added value services (See Location Based Services).
One of the most successful applications of ITS is electronic payment (See Electronic Payment). Non-stop electronic payment supports payment of vehicle tolls on the go. Smart travel cards support fare payment for combined transport services (bus, rail, metro, river transport, parking).
Electronic payment applications integrate technologies for communications, data processing, data storage and microcomputing. The process comprises “front end” and “back-end” activities.
“Front-end” activities are those seen by the user. The most common “front-end” hardware technologies are smart cards, transponders (tags, such as the EZ-pass widely used for electronic toll collection in the USA), and – increasingly – smart phones.
“Back-end” activities are those related to payment processing, account maintenance, customer service and reporting.
Electronic payment is widely used for collecting road tolls whilst the vehicle is in motion. The main components of the system are the transponder (also known as toll tags), the tag reader and the computer system for data processing. Most transponders use Radio Frequency Identification technology (RFID). There are two types of transponders: active and passive. Active transponders carry their own power supply (batteries), whereas passive transponders are powered by the radio frequency (RF) pulse they receive from the reader. Passive transponders are cheaper to buy but they have a shorter communication range and transit less data. Newer models of transponders are designed to allow for integration with smart cards (using built-in slots).
Electronic fare payment systems are commonplace and offer a number of advantages over traditional payment methods:
There are two basic types of electronic fare payment systems: closed systems and open systems.
Closed systems are limited to one main purpose (such as paying transport fares) with perhaps a few additional add-on applications such as paying parking fees. The payment value stored on the card cannot be used on anything other than a pre-agreed and pre-defined activities.
Open systems can be used to pay for other purchases in addition to transport. An example is a credit or bank debit card which can be used with multiple merchants, but fare payment is not an attractive application for credit cards companies because the transactions are high volume and low-value.
A smart card is a card which looks like a credit card in size and shape, but has an embedded microprocessor – in effect, replacing the magnetic strip on a credit card.
Smart cards facilitate the collection and management of payments using electronic media instead of cash or paper transfers. The system consists of two main components – a card and a card reader. Cards can be of the magnetic-stripe type where the reader does most of the data processing – or they can be equipped with a microprocessor, in which case, data processing can take place on the card itself (this is the more popular option).
Smart cards can provide identification, authentication, data storage and application processing. Their use for electronic payments offers the traveller and the transport company/agency several benefits – including time savings, a more convenient payment method, the ability to implement more flexible but complex ticket pricing strategies, lower administrative costs, and better data for future planning. They also allow integrated ticketing strategies so the traveller can use a single card to pay for their transport – whether it be by bus, train, underground/metro/subway or ferries.
Smart cards can be of two types: contact smart cards and contactless smart cards:
A number of other technologies have been adapted for electronic payment – including DSRC/GNSS-based systems and automatic number plate recognition systems.
These systems have been used for or urban tolling or a congestion charge, based on Dedicated Short Range Communication (DSRC) technologies. The standard microwave frequency of 5.8 GHz is used for communication between roadside transponders or antennas and in-vehicle devices.
GNSS-based systems use Global Navigation Satellite System (GNSS) sensors inside the vehicles. This allows a wide range of pricing strategies to be implemented including strategies based on distances travelled. GNSS sensors record time and vehicle position data, which are then processed into trip information and matched against an established pricing scheme. The processing of the data can be performed at a central location or on-board the vehicle itself. The first successful demonstration of GNSS-based pricing systems took place in Germany on the A555 motorway between Bonn and Cologne.
With the wide-spread adoption of smart phones, a number of apps have been developed where the smart phone can act as a payment device. An example is the “paybyphone” app to pay for tolls and parking (See http://paybyphone.com/how-it-works/).