Dynamic System-Optimal Route Choice Model

Abstract

The dynamic system-optimal (DSO) route choice problem requires that travelers comply with a certain driving behavior so that the system-optimal flow pattern, in terms of some predetermined performance measures, can be obtained. This problem is normative in the sense that the transportation system operator has control over the travelers, who must follow the system’s instruction. This assumption is rather restrictive because it is extremely difficult to impose such constraints on travelers, especially in an open transportation system network. As a consequence, travelers who are instructed to take longer routes may unilaterally change routes so as to decrease their travel times, which implies the dynamic system-optimal flow pattern is not stable, and therefore unlikely to sustain itself Nevertheless, the dynamic system-optimal problem is important because the system-optimal travel time may serve as a yardstick by which different flow patterns can be measured. Indeed, the system-optimal flow pattern is desired by many types of traffic control policies such as tolls and signal controls in order to enhance the efficiency of road network utilization.