Real-Time Traffic State Estimation and Travel Time Prediction on Urban Expressway

According to the need of traffic guidance and traffic monitoring system on urban expressway, the paper introduces a method to estimate and predict traffic states and travel time between arbitrary locations on urban expressway. The basic concept is to estimate future traffic states using macroscopic dynamic traffic flow model integrated with extended Kalman filtering £¨EKF£© and the fixed traffic detectors on urban expressway, and to predict dynamic travel time using £¢fictitious car£¢ method. The method is tested on urban freeway in Shanghai by using real-detected data, in which the traffic state estimation model shows good tracking ability, and results of travel time prediction model show that there is a slight difference between the calculated result and the real in free flow, and a relative error at about 10 % mostly in congested flow. The precision and applicability of this mothod are acceptable, and it can be used to provide a basis for traffic control and traffic guidance.