Traffic Equilibria Considering Travel Time Unreliability Based on Perceived Expected Travel Cost

Travel time reliability has been empirically identified as the most important criterion that influences route choice and departure time. The travel route and departure time choice of travelers are determined by road traffic flow, which similarly influence the travel route and departure time choice of a traveler. In this paper, we firstly investigate the interaction of time-varying traffic flow, travel time reliability, and departure time choice, provided that the travelers' route choice decisions are based perceived expected travel cost. Results show that traffic flow changes at different reliability levels, but traffic flow of all routes eventually becomes stable between origin and destination. To formulate the process of realizing stochastic user equilibrium, perceived expected travel cost considering travel time unreliability as traffic equilibrium model are proposed. Numerical studies on a small network are provided to further verify the results of theoretical analysis and show the influence of the reliability level of link on traffic flow assignment.