Policy-based service level-oriented route guidance in road networks: a comparison with system and user optimal route guidance

摘要

The realization of traffic management on a network level is not only theoretically complex, but alsopractically challenging, because of the need to take the traffic management policy of the road authoritiesinto account. In the Netherlands this policy harmonizes the interests of involved stakeholders by means of acommon vision upon the network functioning, expressed in road priorities and corresponding desired servicelevels. Subsequently, network states that reflect the policy objectives need to be realized in a systematic andcomprehensible way.This paper presents a predictive route guidance approach that is able to operationalize the formulatedpolicy in practice. This is achieved by degrading and restoring target service levels of routes according totheir difference in priority with respect to the network performance. The control approach consists of afinite-state machine that determines the desired service levels based on predicted traffic conditions. Theseservice levels are used in a feedback controller as setpoints for the desired travel times, resulting in thecorresponding output signal of a Variable Message Sign.By means of a test case, the finite-state machine is compared to an optimal (Model PredictiveControl-based) route guidance approach that realizes system optimal conditions and to a feedback controllerthat realizes user equilibrium conditions. The evaluation results show that the finite-state machine is able toprevent or limit the effects of phenomena that cause decreased network production in a comprehensible andefficient way, while taking the interests of the road user into account.