Equilibrium trip distribution/assignment with variable destination costs

A ‘user-equilibrium’ trip distribution/assignment model is developed, which includes an endogenous destination cost for the conduct of a given activity at the destination. Destination costs are determined endogenously, as increasing functions of the number of trips to the destination. Link travel costs are increasing functions of link volumes. Travelers are assumed to choose the itinerary of deterministically perceived least cost. Activity performers are assumed to choose among alternative destinations so as to minimize the randomly perceived total cost of activity and travel. It is shown that the model always possesses a unique solution, when destination costs reflect either positive or negative externalities. An algorithm for obtaining that solution is described. The model is well suited to the analysis of a variety of issues concerning the effects of road pricing policies on urban travel demand and, conversely, of toll-based traffic management strategies on economic performance.