A Dynamic User Equilibrium Model for Traffic Assignment in Urban Areas

Abstract

In this paper, we present a model for dynamic traffic assignment in urban transportation networks. The transportation demand is given by the number of users traveling from the same origin to the same destination and having the same desired arrival time. The model determines for each user both the path and the departure time so that he cannot decrease his disutility by unilaterally changing his departure time or/and his path. The disutility measure is given by a generalized travel time function taking into account total path travel time and schedule delays. Departure time choices are restricted to a finite set of instants, but users with same choice of departure time and same first arc on selected path are loaded uniformly on the network during a time interval whose lower bound is the chosen departure time. A finite dimensional variational inequality formulation of the problem is given and the existence of a dynamic user equilibrium is proved. A heuristic method is proposed to compute a dynamic user equilibrium. Numerical results are provided.