Algorithm of VMS site optimization in network based on comprehensive route impedance

Variable Message Sign is an important equipment for route guidance. Its location influences the redistribution of traffic flow in traffic network. The comprehensive route impedance consisting of section travel time and intersection delay reveals the state of road effectively. Route impedance is calculated by real traffic data of section travel time and intersection delay. The optimal goal is to make the value of utility function maximum. On the basis of comparing the objective function value, the final scheme is the scheme with maximum value of utility function. The real network between Xizhimen interchange and Fuxingmen interchange was applied in an instance. Using the algorithm of VMS site optimization based on comprehensive impedance, the result of the instance fits well to real situation and the trend of VMS construction in this area.