Tram Signal Priority Under Arterial Signal Coordination

As a medium-capacity of rail transit, the flexible, environmental and comfortable modern tram is welcomed by a lot of citizens. However, compared with social vehicle and bus, tram has its own unique driving characteristics, thus the traditional signal control method will have a negative impact on its operational efficiency and safety. According to the driving characteristics of tram, driving environment of mixed traffic and the short distance between intersections, it is an important topic about how to provide signal priority when the trams cross the intersections.Based on tram’s driving characteristics and its impact on other traffic flow; this thesis researched signal priority control method for the tram when crossing the intersection. The main purpose of this thesis is giving tram signal priority to keep its service quality, while ensuring the effectiveness of other vehicles.Firstly, tram’s driving characteristics and the impaction of the tram signal priority on other vehicles were analyzed in the thesis; then the tram signal priority control system was designed by the detailed analysis. Two subsystems were included in this system:road signal coordination control subsystem, tram signal priority subsystem, and four modules were included in this system: traffic information detect module, intersection signal control module, progression signal control module, tram signal priority control module.Based on traffic information which was obtained by traffic information detect module, the signal cycle, green ratio and effective green time were calculated by intersection signal control module. On the basis of intersection signal control module, intersection delay was considered as the objective function by progression signal control module, and the phase at each intersection along the arterial was optimized by using genetic algorithm in the progression signal control module. On the base of tram holding strategy, green time extension, and early green, tram signal priority was proposed by tram signal priority control module.Finally, the simulation model was designed to evaluate the performance of the proposed tram signal priority system. The results show that the models can effectively reduce vehicle delay, accomplish tram signal priority and achieve the tram punctuality.