Coordinated ramp metering control with variable speed limits

In this research project funded by the Swiss Federal Roads Office, the aim is to develop an effective ramp-metering strategy to reduce congestion on Swiss highways.

The project aims at addressing challenges that arise from particularities of Swiss highway infrastructure, most notably short access ramps built near urban areas. Conventional ramp-metering strategies, where traffic onto the highway is regulated one ramp at a time, are unlikely to be effective, as queues forming on the ramps could easily spill back into cities, replacing congestion on the highway by congestion in the city.

An effective ramp-metering strategy demands a global approach that integrates data from real-time monitoring of congestion on a large portion of the highway network to control the influx of cars on all highway access points simultaneously to adapt to the queue on the highway. In addition, variable speed limits enforced using changeable message signs would help smoothen the flow of traffic on the highway.

Two frequently congested highway segments will provide traffic data and act as test sites. After upgrading the current traffic monitoring infrastructure to match the requirements of a ramp metering approach, the data obtained from these sites will be used to test the feasibility of such an approach method using computer simulations. Ideally, the project would then be pursued with an full-scale field implementation of their strategy.

This two-year research project is being conducted Professor Nikolas Geroliminis of the Laboratory of Urban Transport Systems.

News release (EN, FR)

Principal investigator Prof. Nikolas Geroliminis
Project managers Mohsen Ramezani, Mehmet Yildirimoglu
Sponsor Swiss Federal Office of Roads (ASTRA/OFROU)
Period 2012-2014
Laboratory LUTS
Collaboration TRACE