Dynamic Traffic Assignment Models

Abstract

This paper is concerned with the modelling of the Dynamic Traffic Assignment Problem for predicting the flows of urban transportation networks, mainly at peak periods. We descibe one Dynamic Traffic Assignment Model that is mainly based on the assumption that the time spent by a vehicle on a link may be decomposed into a fixed travel time, plus a waiting time spent in an exit queue which resides on the same link. This model leads to a network structure that is a temporal expansion of the base network including the queues. Therefore, this Dynamic Traffic Assignment Model may be viewed as a classical Static one over the expanded network. Then we describe a second approach that is mainly based on the assumption that the users know at each period of time, the travel times on the links of the network, but not for the next periods, and that, at each node, they enter their actual shortest path. Numerical tests have been performed with the transportation network of the city of Hull (Canada).