Ten years of ramp-metering in the Netherlands

Ramp metering is the management of traffic on an on-ramp, dependent of the traffic conditions on the motorway and the on-ramp. The main purpose is the improvement of traffic conditions on the motorway, taking into account the conditions on the on-ramp and surface roads. In 1989 the first ramp-metering system in the Netherlands became operational on the S101 on-ramp to the AlO-West near the Coentunnel. The system was a great success and was followed by a second pilot on the Delft-Zuid on-ramp to the A13 in the direction of Rotterdam. This also turned out to be a success. Based on this results more on-ramps were equipped to a total number of 20 by the end of 1998. On eight of these locations an assessment study was done. In the paper these assessment studies and the effects of ramp metering on capacity, flow, speed, and travel time, are discussed. It describes the different algorithms used and their impact. It concludes with some remarks about the assessments and draws some conclusions from them