Multiclass Stochastic User Equilibrium Model with Elastic Demand: Considering Systematic and Accidental Delays

This paper proposes a multiclass, multidelay stochastic user equilibrium model with elastic demand (MC-MDSUE-ED) that explicitly considers both systematic delay and accidental delay in the route choice decision process. This new model hypothesizes that for each user class and each origin–destination (O-D) pair, no traveler can reduce his or her “multi-delay travel time,” defined as the systematic delay plus accidental delay, by unilaterally changing paths. The actual travel demand for each user class between each O-D pair satisfies its elastic demand function. Travel time budget and robust optimization theory are used to compute the systematic delay and accidental delay, respectively. The MC-MDSUE-ED conditions compose a cobweb model. A self-adaptive bisection algorithm that converts the problem with elastic demand to a series of problems with fixed demand was developed for solving the cobweb model. A path-based quasi method of successive averages was used to solve the MC-MDSUE model with fixed demand. Numerical examples illustrate the essential ideas of the proposed model and the applicability of the proposed solution algorithm.