Variable Speed Limits Control Based on Accident Rate before Freeway Main Toll Station

Abstract

When it comes to VSL (variable speed limits) control before a freeway main toll station, setting excess VMS (variable message signs) will result in a waste of resource and information redundancy. At the same time, too few VMS can not manage to guide and smooth the traffic flow due to the poor continuity of VMS and further guarantee traffic safety. Besides, different VSL programs may need different number of VMS. However, there is no research to date proposing a method to determine the number of VMS and corresponding VSL programs. Thus, an optimal model aiming at minimizing the accident rate is established to determine the number of VMS, taking economic cost and speed limits as constraints. Accident rates for a different number of VMS are solved out, according to which optimal number of VMS is determined, and finally, corresponding VSL control method is proposed.