This paper describes trials carried out at the Boulevard Périphérique (BP) of Paris and near the Coentunnel of Amsterdam, of traffic responsive ramp metering strategies. ALINEA, the Rijkwaterstaat, and the W & J (Wootton and Jeffreys) strategies were used to investigate vehicle responsive isolated ramp metering measures. Co-ordinated ramp metering strategies were investigated using METALINE and SIRTAKI. Details of both strategies used, along with a brief description of the sites at which they were tested, are provided, as is a summary of the main findings. The results indicate that the main differences between the strategies are as follows: a) ALINEA is based on feedback, whereas The Rijkwaterstaat and W & J strategies are based on feedforward; b) the Rijkwaterstaat strategy uses volume measurements whereas the W & J strategy uses speed and volume measurements, and the ALINEA strategy uses occupancy measurements; c) ALINEA is based on integral control; the Rijkwaterstaat strategy uses proportional control. Details of future work aimed at comparing the various different systems and evaluating their ability to decrease traffic congestion are provided.
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