Integrating adaptive queue-responsive traffic signal control with dynamic traffic assignment

Recently, with their promise for Intelligent Transportation Systems (ITS), dynamic traffic assignment (DTA) and adaptive traffic-responsive signal control have received greater attention. However, the mathematical models used to describe the interaction between these two systems are tenuous and considerable effort is still needed to improve the limitations described in the existing literature, especially regarding the solution capabilities, the oversaturated-queue phenomena, efficacious estimates of link travel disutilities, and a reliable evaluation method. The objectives of this research are to implement non-linear programming techniques to model dynamic traffic assignment and adaptive queueresponsive traffic control separately, and develop an iterative procedure to solve the components of traffic assignment and signal control by minimizing the overall system-wide signal delay.;For traffic signal control, total intersection delays in a network are minimized by allocating appropriate time splits. The generalized intersection delay model in the Highway Capacity Manual was used to take the oversaturated queue problem into account.;Improvements to DTA methods include formulating the dynamic user-optimal route choice model as a variational inequality (VI) model, calculating the expected travel time on each link using a simulation model, applying a relaxation algorithm to produce an equivalent optimization formulation of the VI model, and developing a solution algorithm which can be implemented using existing traffic software.;There is not much hope for developing exact solution algorithms to solve these two models simultaneously because of the computational complexity of the non-linear programs. Therefore, a heuristic procedure involving an iterative optimization assignment is used to solve the combined models.;A computerized procedure was developed to implement the solution procedures and a numerical example of a traffic network was prepared to test the program. An accepted traffic simulation model, CORSIM 5.1, was used to validate the results for both static and dynamic optimizations. The test results showed that dynamic traffic assignment with adaptive traffic-responsive signal settings reduced the network-wide delays by nearly 15%.