This paper is concerned with the use of origin-destination (O-D) information to support ramp-metering strategies for motorways. The work reported here relates to workpackage 443 of the DRIVE project ODIN. The first section of the paper presents a brief review of existing ramp-metering strategies. The second section discusses the possibilities offered by O-D information; of particular importance is the level of accuracy and prediction that is required, as well as the level of temporal resolution. The range of techniques for the estimation of dynamic O-D information are also considered. The main section of the paper presents the results of a simulation study using the CONTRAM program. A series amp-metering strategies are tested. The overall objective of the strategies is to keep flow at critical points below critical levels, above which congestion would build. Gating strategies - preventive and clearance - are employed and three types of strategies are tested, namely: local metering, nearest neighbour metering and global metering. The effect of the use of the secondary network and Variable Message Signs (VMS) is considered, but not simulated. The simulation results demonstrate the benefit obtained from the incorporation of O-D information in ramp-metering strategies.
Samenvatting