Optimization for Urban Traffic Assignment by Congestion Toll Levied on Regional Expressway

The objective of this paper is to study the toll standard of regional expressway network so as to optimizing traffic assignment and consequently reducing the holistic cost of the network. Based on Wardrop´s principles and expense analyses, a function called generalized expense model is brought forward to calculate the optimal toll rate. Genetic algorithm (GA) is applied to solving the model according to its characteristics. The paper takes a network planning as an example for analysis. The traffic distribution without toll controlling is depicted by VISUM traffic simulation. Contrast analysis, which is made between the model solution and the simulation results, demonstrates that the model is valid and practicable.