COSMOS-Congestion Management Strategies and Methods in Urban Sites
WOOD K, Transport Research Laboratory, BIELEFELDT C, Consultant to MVA, BIORA F, MIZAR Automazione SPA, Italy, KRUSE G, Siemens A G, Germany
Urban congestion is one of today's main traffic problems. Congestion aÛfects in particular radial routes to the town centres in the morning and afternoon peak, and many central business districts even outside the peak periods. The main cause for congestio
Urban congestion is one of today's main traffic problems. Congestion aÛfects in particular radial routes to the town centres in the morning and afternoon peak, and many central business districts even outside the peak periods. The main cause for congestion is oversaturation of the networks, but the situation is worsened when incidents occur. The EU project COSMOS is designed to reduce the adverse effects of congestion, both regularly occurring and due to incidents.
The solutions that are potentially the most effective ones are either increasing the road supply or decreasing the traftic demand. The first is a solution of the past, and, today, is generally no longer an option in urban areas because of both physical and environmental constraints. Decreasing traffic demand through demand management is certainly an option for the future, which could have a major impact on congestion reduction, but will not be widely introduced for a long time. Therefore, Urban Traflic Control (UTC) and network signal control as a central part of it, will have to cope with ever increasing traftic problems for years to come, and will have to be able to deal with congestion.
Most of the congested routes and road networks in urban areas are equipped with traÛEc signals. However, the signal programs are generally not well prepared to deal adequately with congestion and, even more so, with incident problems. All of the current main contenders for on-line signal network control in Europe (SCOOT, UTOPIA, PRODYN and MOTION) have originally been designed to optimise unsaturated traffic. They are doing this in different ways and using different types of optimisation criteria. The more mature of them have been developed to provide tools to improve the response to congestion and incidents. However, none of them, so far, contains general procedures for Congestion and Incident Management (CIM).
The COSMOS project is developing, and will validate and demonstrate new procedures for reducing and, where possible, preventing congestion in densely trafficked urban areas. These procedures comprise:
* special CIM modules and Automatic Congestion and Incident Detection (ACID) which can be included in any on-line network signal control systems, and
* strategies for rerouting trafiic to make the best use out of the capacity at junctions and in the links between them.
Developers and users of three systems, SCOOT, UTOPIA and MOTION, are working in COSMOS. These three UTC systems already incorporate, albeit to different degrees, some functions for Automatic Incident and Congestion Detection, and further hctions for relieving the situation once problems have been identified. The new CIM strategies are to be incorporated in the existing systems and will be implemented in London, Piraeus and Torino for verification and demonstration. The paper describes the methods that have been developed to modify the control traffic signals to reduce the effects of congestion, the common control strategies that are generally applicable. It then describes the implementation in London in more detail to show how the strategies can be used in a practical system.
Association for European Transport