Fuzzy route choice model for traffic assignment

In order to represent traffic assignment on a road network, we propose a ne w route choice model taking account of the imprecisions and the uncertainti es lying in the dynamic choice process. This model makes possible a more ac curate description of the process than those (deterministic or stochastic) used in the literature. We assume that drivers choose a path all the more t han it is foreseen to have a lesser cost. The predicted cost for each path is modelled by a fuzzy subset which can represent imprecision on network kn owledge (e.g. length of links) as well as uncertainty on traffic conditions (e.g. congested or uncongested network, incident...). The costs of all pos sible paths are compared and result in an attractiveness degree for each pa th. Various comparison indices can be used to represent the different possi ble natures of drivers when making their decisions (pessimistic/optimistic, risk-taking/risk-averting). The fuzzy choice model was compared with the L OGIT model (a widely used stochastic discrete choice model) and has been pr oved to be able to find the same results. The effect of Advanced Travellers Information Systems (ATIS) on drivers is modeled as a modification of the imprecision or the uncertainty of the predicted cost of a route. (C) 2000 E lsevier Science B.V. All rights reserved.