Traffic Models for Dynamic Assignment

Abstract

The purpose of this paper is to illustrate the effects on estimated traffic flow of different traffic models in solving the dynamic traffic assignment problem. We will compare two distinct traffic models, the kinematic wave model and the flow model. We will show that the model’s resulting estimates differ substantially. The kinematic wave model is regarded as the more realistic of the two but it is difficult to work with, requiring large computational effort, while the flow model is less realistic but is computationally more tractable. The flow model has been adopted widely in the development of existing dynamic traffic assignment techniques (Wie, Friesz and Tobin, 1990; Ho, 1990, Vythoulkas, 1990a; 1990b; Carey, 1986; 1987; 1988). According to this model, the outflow from each link is a function of the mean density on the whole link.