Study on Freeway Optimal Control Based on Evaluation of Dynamic Travel Demand

According to the information of the dynamic travel demand evaluation, freeway optimal control model is proposed based on the hierarchy theory. Four control modules are introduced including the travel demand forecasting module which predicts the total travel demands for a long time and determines the upper bound of the queue length; the global optimal control module which predicts the traffic state and identifies the constraints for the link (ramp) of network; the travel demand evaluation module which estimates the real-time traffic conditions; and the local feedback control module which calculates the ramp control rate according to the evaluating information of the real-time traffic conditions and the optimal results from the previous module. The simulation results show that the control system is of good dynamic performance. It coordinates the benefits and optimizes the whole performance of the freeway network.