/ the Multi - Modal Traffic Assignment Problem

Traffic equilibrium analysis 4~s provided useful insight into the transportation planning proce~s. Even for deterministic demand models, though, the state-of-the-art does not include any efficient approach that is applicable for general equilibrium models. Existing convex programming approaches, which are efficient and guarantee convergence, are restrj.cted to single commodity (mode, user class) flow problems with inv~rtable demand functions. In this thesis, we first show that convex p~ogramming approaches cannot be generalized to broader, and yet still realistic~ settings. Secondly, we introduce a new approach that can be applied to multi-commodity flow problems (including multi-class, multi-modal, and destination choice user equilibrium models) with arbitrary deterministic demand functions. The approach consists in formulating the traffic equilibrium problem as a nonlinear complementarity problem. Based upon. this formulation, we propose and prove general existence and uniqueness theorems, and we develop a linearization algorithm. We also present cOlnputational results on a variety of test problems to illustrate the generality and the efficiency of the algorithm. Thesis Supervisor:' Thomas L. Magrtt.lnti Title: Associate Professor