TWO-STAGE FUZZY CONTROL OF ISOLATED INTERSECTION

The general objects of urban traffic signal control are ensuring traffic safety and improving traffic efficiency, but we suggest that traffic fairness also should be emphasized during the signal control process. A two-stage fuzzy traffic signal control model for isolated intersection that traffic efficiency and fairness are emphasized simultaneously is proposed. The model is composed of two fuzzy controllers: Green Phase Selector is applied to select green phase based on the detected number, average waiting time and arrival rate of vehicles on all entry lanes; Green Time Regulator is applied to set green time for the selected phase based on the detected number and arrival rate of vehicles on the lanes belonged to this phase. For improving the control efficiency, fuzzy rules and membership functions of two fuzzy controllers are optimized. Simulation experiments show that the unoptimized model is more efficient and fairer than vehicle-actuated control model and Pappis and Mamdani's model, and the optimized model has the highest efficiency. Simulation results illustrate that our model design is scientific and effective, and it is helpful for improving urban traffic signal control.