Optimal Traffic Assignment with Elastic Demands: A Review Part I. Analysis Framework

This study reviews, in two parts, the formulation, interpretation, and solution methodology of the traffic assignment problem with elastic demands, originally described by Beckmann, McGuire and Winsten. This paper (Part I) defines the different possible modes of traffic assignment in a network and identifies the economic rationales of the associated extremum formulations. The accompanying paper (Part II) examines algorithmic approaches for calculating the resulting flow patterns. The assignment problem is characterized as an interaction between users and operators of the transportation system, analogous to the interaction between consumers and producers in the marketplace. The notions of “user-optimization” and “system-optimization” thus acquire congruent interpretations, expressed by a systemwide maximization objective.