Timely sharing of traffic and transport information through electronic systems is a cornerstone of ITS network management projects and integrated network operations. It requires sufficient investment in traffic monitoring and surveillance technologies by the agencies responsible for road network operations. It also requires agreement on a set of common standards for data exchange: message sets, protocols, location referencing. Software models and telecommunications protocols are also crucial, but are driven by much larger markets than ITS – these non-transport-related developments need to be monitored and taken into account.
It is necessary to choose data communications standards and protocols that are common to all control centres, including the police and emergency services. This requirement will impact on any existing TCC operated by the police or municipal authorities – possibly involving an upgrade of legacy systems. An ITS Strategic Plan for the country or region will need to address these issues and make recommendations. (See Developing an ITS Strategy)
In many cases, data can be shared by multiple ITS services. For example, traffic control measures – such as lane control systems – can be coupled with traffic enforcement systems that use the same traffic monitoring and camera installations. Similar options for integration are electronic fee collection, traffic flow monitoring and traffic information services.
There are national and international guidelines and standards on data coverage and data quality and how the data is coded – including:
In many countries, budget limitations prevent comprehensive investment in the infrastructure and organisational arrangements needed to achieve adequate data coverage and quality. Decision makers need to understand that ITS services will underperform if data quality and coverage is poor.
Transport network databases need constant maintenance to keep up-to-date. Careful checking is essential to avoid errors which can lead to features being incorrectly located.
New data sources do not negate the necessity of having permanent network monitoring infrastructure in place, to provide timely and accurate information about traffic flow and conditions on critical parts of the road network. Project planners will need to consider the extent of network coverage and the level of resolution required – in terms of road links and nodes to be monitored and the degree of resolution for specific time-periods.
Priority should be given to road sections with high traffic flows and high occurrence of incidents. Traffic monitoring and transmission of data in real-time will make it easier to respond rapidly to accidents and emergencies. For road safety or other operational reasons, it could be a priority to equip known hot-spots – in advance of comprehensive network-wide coverage.
Any traffic monitoring system will need operational support – in the form of a contractor to supply and maintain the equipment, software and provide the data integration services that will provide network monitoring “intelligence”.
Traditionally traffic surveillance is provided by a network of fixed traffic detection systems (loops, radar, cameras and other above-ground detection). Equipment reliability and the requirement for maintenance over time are key considerations in making choices. A regional maintenance contract will be necessary to cover the fixed installations.
Point-to-point journey time data for the network (historic and in real-time) is a useful resource for journey planning and logistics support. Continuous non-invasive point-to-point tracking of individual vehicles is now possible at very low cost. Some road authorities use aggregated data (made anonymous) displayed on VMS to provide drivers with an expected journey time between key points on the network.
Vehicle tracking and data capture techniques include ANPR license plate recognition cameras or – more recently, point-to-point monitoring of Bluetooth signatures. Bluetooth sensors have been used successfully for point-to-point average speed monitoring as a cheaper alternative to Automatic Licence-Plate Recognition. (See Vehicles and Roadways)
Floating Car Data
An increasingly attractive option for large scale data collection at relatively low cost is the use of Floating Car Data (FCD). The widespread availability of smart-phones that incorporate GPS has made it easy to obtain data on vehicle paths, speeds and journey times. A fleet of vehicles equipped with a location system, like GPS, can act as “traffic probes” that provide a rich source of data for monitoring network conditions in real-time and for keeping track of network performance. Data on point-to-point route choice and journey times (made anonymous to protect privacy) will contribute to network planning, incident response, traffic management and control.
Social networks and “Crowd sourcing” can also be used to gather information on network conditions using smart-phone applications. Crowd sourcing of traffic data is still in its infancy but represents an important opportunity where there is no investment in fixed detection. A road operator could explore cooperation with developers of smartphone applications to produce a valuable service to road users in the region.
In the city of Hefei, China, a total of more than 3,000 public vehicles were equipped with GPS and GSM mobile telecommunications to continuously provide on-line traffic data to the control centre. The data were then merged with camera and loop data to enable good coverage of the urban road network.
In South Africa, a national ITS network monitoring and management scheme was developed by the South African National Road Agency (SANRAL). This scheme covers over 560 km of national road networks in the three regions of Gauteng, Kwazulu-Natal and the Western Cape. Under a BBFO contract (Design, Build, Operate and Maintain), the project includes:
In Cebu, in the Philippines, a pilot project is being developed in collaboration with the Metro Cebu Taxi Operator Association, using GPS-enabled mobile phones in a sample group of taxis – to support traffic data collection and dispatch. By tracking the vehicles’ travel speeds and locations, traffic status data is collected. The application benefits the participating taxi companies by incorporating a visual interface showing their vehicle locations – providing support for their taxi dispatch operations.
In Hefei China, a high penetration rate of more than 5,500 probe vehicles (police patrol cars, trucks and buses) are deployed in combination with loops, radar and cameras – to collect data. The objective is to develop and implement an up-to-date traffic management system – which integrates traffic data collection and the broadcasting of traffic information services to traffic operators, travellers and drivers. The Floating Car Data (FCD) System, enables the user to visualise the traffic flows and assess the traffic situation – and then broadcast traffic information to road users through Digital Multimedia Broadcasting (DMB). This uses TPEG (Transport Protocol Experts Group) – a coding standard for detailed traffic and journey information.
Crowd sourcing is becoming an important data source for traveller information services – and is increasingly popular in Egypt as use of the internet and smart phones become more widespread. It provides a platform for informing the public about the status of traffic.
A contract for data collection operations can include performance-based requirements – where the contractor receives a payment incentive when the required level of service is achieved, or a financial penalty when it is not. Potential contractors are required to propose their own solutions and designs – and provide proof-of-concept to demonstrate compliance with requirements. This results-based approach depends on strict data quality benchmarks being defined in the contract – including data types, network and time period coverage, quality indicators (such as data accuracy, confidence, delay or latency of communication), availability, breadth and density of coverage.