The joint signal timing and route choice on networks considering increment

Selecting the length of the increment is important in solving the optimal signal timing (OST) and the dynamic user optimal route choice (DUORC) problem. How large should the increment in the solution process be? The study of this problem is rare. In this paper, the OST and the DUORC problem was studied with the consideration of assignment increment. The problem is modeled as a three-level problem and the experimental study is done. The first level is setting the increment. The second level minimizes total travel time.  The third level is a variational inequality (VI) DUORC model. The result of the experimental study shows that a smaller increment can increase the precision of the solution. Since the signal cycle at an intersection cannot be less than the minimum cycle, the study indicates that a small increment is preferred in solving the OST-DUORC problem as long as the minimum green time is reached. Furthermore, this paper presents a conception of a new OST-DUORC travel guidance system, including the framework of the system and the algorithm for it. With the method, the traffic center selects an appropriate increment based on the result of this study, and then finds the OST for intersections and the optimal routes for travelers by running the second and third level model. The method helps implement a transport system integrated with a traffic control system and a DUORC guidance system.