Dynamic traffic management

Summary

The collection, processing, integration and presentation of reliable data on traffic flow can make a valuable contribution to easing congestion and reducing the negative environmental impacts of transportation.

Implementing sustainable mobility

When data can be exchanged, information can be spread and a variety of services can be supported (e.g. journey planning, traffic regulation, variable message signs and incident management). The optimisation of the transport network requires information on traffic flow, travel times, the consequences of lane closures and accidents etc.

As in many other cities, it has been difficult for the general public in Graz to obtain reliable information about the current traffic situation. The city had several systems operating in parallel, some of them very modern. These included the traffic control system (a computer-based vehicle location and operational control system), a street database and an online taxi fleet management system. These systems are run by different operators and were not previously interlinked.

The new, dynamic system, by incorporating information from different sources and using different channels to distribute information, aimed to:

• reduce traffic emissions in absolute terms by keeping traffic flow steady;
• reduce congestion hours by keeping the traffic flow away from obstacles and congestion and by guiding drivers to parking spaces or park and ride facilities;
• encourage a modal shift away from the private car; and
• reduce fuel consumption and negative environmental impacts.

Progress

The TRENDSETTER project comprised the following activities:

• Online presentation of the current traffic situation: An innovative methodology was developed to combine traffic data from the fleet management system of taxi operator Taxi 878 (floating car data, or FCD) with data from automated traffic counts and from the traffic control optimiser MOTION, making it possible to obtain real-time traffic information.
• Strategic traffic control/management: Existing network control was extended to enable strategic and dynamic reactions to events such as congestion, tunnel and lane closure etc.
• Acceleration of public transport: Using radio signals from the onboard computers of the public transport company’s traffic management system, traffic lights are influenced in favour of public transport vehicles.
• Information management: Strategic decisions made by the police traffic control centre, as well as information provided to traffic participants via Internet and mobile phone, are based on the online and real-time information about the current traffic situation.

Outcomes

The traffic control system comprised:

• the database of the street network, containing data about routes and traffic statistics;
• the radio control centre of the company Taxi 878, which has a GPS for its taxi fleet that records the actual position and route of its taxis (220 cars in the fleet have a GPS transmitter that automatically reports its position to a central database every 20 seconds);
• the central traffic computer, which records all data from over 500 counting loops; and
• an Internet platform.

Although by the end of the measure not all data sources had been completely integrated, the system was partly in use and results were good. The rerouting or rescheduling of trips reduced congestion and kept traffic flow steadier, thus reducing emissions. Public transport journeys were also made faster, since some buses and most trams were prioritised at many traffic lights.