Road Network Operations
& Intelligent Transport Systems
A guide for practitioners!
Road Network Operations
& Intelligent Transport Systems
A guide for practitioners!
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 right-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
Print