Study On Bus Signal Priority Control Method Considering Pedestrian Time Benefit At Commercial District

The implementation of public transport priority strategy is an important means to alleviate the current urban traffic congestion problem.As the key area of the urban road network,the signal control scheme is reasonable directly affects the overall road network’s ability to solve the problem.The traditional bus signal priority control method starts from the time benefit of bus and social vehicles.However,for the special area like commercial district,the location of the area attracts a large number of pedestrians.If ignoring the time effect of pedestrians,the overall delay at the intersection will be increased instead of being decreased.Therefore,it is of great significance to study the bus priority control method at commercial district considering pedestrian crossing for improving the traffic efficiency.Based on the traffic characteristics of pedestrians in the commercial district,this paper determines the speed and arrival distribution of pedestrians in the commercial district through the movement detection algorithm.According to the characteristics of pedestrian and vehicle flow in different periods in the intersection,the change of the overall delay in peak and flat peak periods is analyzed respectively to propese the signal control method.The research contents of this paper are as follows:(1)Studying pedestrian traffic characteristics at commercial district.According to the characteristics of video stream recorded from the vertical perspective,a pedestrian flow statistics algorithm based on movement detection was proposed.In the movement detection stage,after the background modeling of the video image was completed with the mixed gaussian model,the Otsu algorithm was selected and the image was morphometric processed to eliminate the shadow of targets to improve the detection accuracy.In the matching counting stage,the pedestrian flow in each direction is counted by setting the pedestrian detection frame and judging the positive and negative displacement of the centroid of the detection frame.(2)Studying the delay changes in intersections at different periods.According to the traffic flow characteristics of intersections in different periods,the intersections are divided into doublepeak period and single-peak period.In the peak period,the influence of pedestrian crossing the street on motor vehicles is considered,and the pedestrian phase is added to evacuate pedestrians twice in one cycle.At low peak period,the original phase scheme remains unchanged.According to these rules of phase schemes at different time periods,the delay triangle method is used to quantitatively analyze the delay changes of pedestrians,buses and social vehicles.(3)The priority control model of bus considering pedestrians crossing the street was established.Pedestrian,bus and social vehicle delay are selected as optimization objectives to establish a multi-objective optimization model considering pedestrian crossing the street.The parameters among the targets were determined by the expert scoring method and the Particle Swarm Optimization(PSO)algorithm was used to solve the model.(4)Example simulation and verification.The simulation of the selected example mainly includes the following two parts:(1)Using VISSIM with its own Vis VAP module to write the logic algorithm of bus priority control;(2)In order to determine the appropriate time about the actual green light extension,the extension time of two periods is calculated respectively according to the traffic volume by field investigation,and the time of delay is selected as the evaluation index to evaluate and analyze the three control schemes of the current fixed timing,peak period and low peak period respectively.The results show that the proposed control model can guarantee the time benefit of pedestrians and buses when the overall traffic efficiency is improved.