A model for determining optimal variable message sign locations

Variable message signs (VMS), a component of intelligent transportation system (ITS) technologies, have been more and more widely applied in urban traffic management. A new model to determine optimal locations for VMS has been proposed in this paper. First, the optimal VMS location problem is formulated as a bi-level programming problem which takes into account the interaction between VMS and network-wide traffic flow distribution. The upper level model of the bi-level problem aims at maximizing the benefits of the VMS system regarding the amount of information provided by VMS. The lower level model is a stochastic user equilibrium traffic assignment model. Second, the solution algorithm for the bi-level model is presented. Next, the validity of the new model is verified by numerical analyses through a case study. Research results of this paper provide a technical tool to make plausible decisions regarding optimal VMS location plans.