Optimization of Signal Timing at Critical Intersections for Evacuation

Aimed to make the evacuated vehicles leave the evacuation zone as quickly as possible, a bi-level programming model is proposed to determine the signal timing at critical intersections (CI) by means of dynamic traffic simulation. The upper-level designs the optimal signal timing plan with the objective that minimize delays of critical intersection approaches inside of the evacuation zone based on known traffic distribution, while the lower-level simulates the dynamic propagation process of evacuated vehicles in the evacuation zone based on CTM and the principle of User Equilibrium. To demonstrate the effectiveness of the proposed method, we apply the model and algorithm based on the survey of parking lot, the urban street network around Nanjing Olympic Sports Center, to obtain the traffic volume of each road section, arrival distributions of evacuated vehicles at CIs, and optimal signal timing plan of each CI. It can be seen that the proposed method can effectively solve the integrated problems of signal timing optimization and dynamic traffic simulation.