Research On Highway Variable Tolls Based On System Dynamics

With the economic development of our country, the travel demand and private car number have increased remarkably. However, under the circumstance of scarce road resources, there is severe road congestion during peak period. At the same time, the highway has to leave unused during low peak period. The traffic distribution unequally not only lower the the utility of highway users, but also rise the highway operation cost.There is a lot of factors which will affect highway charging standard formulating. This article select several which is representative from the view of both highway users and operators, such as GDP?vehicle amount and road maintenance cost during service period. Divide the highway service time into peak and low peak period according to bimodal travel characters and set different charging standard. Next day's travel choice will be affected by Logit utility function. Build system model using system dynamics on this basis and divide it into social economy submodel, road maintenance submodel and travel choice submodel. According to the simulation model to show the impact of travel demand to change the transport policy of the highway, and then discuss the traffic management policy change for the use of highway cost changes.At last, use software “Vensim” to take Chengdu-Chongqing Expressway(Sichuan part) as example for empirical analysis. Through the simulation to compare the influence of social cost and income for different charging standard between different period, and finally get a relatively optimal scheme which has lower social cost and higher income. The system dynamics method overcomes the drawback which set standard from only one side and it can provide more reasonable and targeted advices and demonstration.