Establishment and analysis of traffic assignment model under the user equilibrium and system optimization principle

• 1、School of Transportation, Southeast University, Nanjing 210096, China

Abstract：In order to better understand the difference and connection between the user equilibrium (UE) and system optimization (SO) principle, the UE model based on route cost function derived by mathematical theory is established. The equivalence of this model to Wardrop first principle is also proved. Based on this model, the relationship between link and route cost function is studied. Through calculating, we find that route cost function can be created by link cost function which is passed by route. Compared to route cost function of UE principle, route cost function of SO principle is just a special case. The UE model and SO model are interpreted from physical and geometric points of view of. By constructing different link cost functions, the UE model and SO model can be converted into each other. These results show that the derived model can provide new perspectives and new methods for traffic assignment algorithm.

Keywords： user equilibrium (UE) system optimal (SO) route cost function model significance model transformation