Traffic state feedback guidance strategy under long update intervals

Update intervals for guidance strategies used in variable message signs have to be long due to limitations of detectors and display format of broadcasting guidance information. A guidance strategy is introduced based on the traffic state instead of travel time. A traffic state feedback guidance strategy is obtained by utilizing relative stability of traffic state. A hybrid strategy considering travel time and traffic state is proposed as a solution of conflict between time-varying demand and long intervals. Simulation results show that the traffic state feedback strategy is able to meet the practical requirement both in the stability and accuracy under long update intervals, and the hybrid strategy further improves the accuracy.