Institute of Transportation, MOTC

　　A bilevel model is formulated to represent a dynamic signal control problem. In the upper level, total network travel time is to be minimized, while in the lower level a variational inequality formulation is constructed to characterize dynamic user equilibrium. Since the function of link inflow with respect to green time at the corresponding intersection is not in closed form, the derivative, which is normally used to search for an optimum, cannot be obtained. As a result, an alternative approach, usually named sensitivity analysis, is adopted for solution.
　　In the context of sensitivity analysis, the technique of computing general inverse matrix is exploited. By means of chain rule, the sensitivity information can be further used for searching dynamic user equilibrium. A numerical example is then used for testing. Few remarks are also given in the end to conclude the paper.