Study On Traffic Safety Of Irregular Intersections Based On Simulation And TCT

Urban signal intersection is an important part of the urban traffic network,where motor vehicles,non-motor vehicles and pedestrians from different directions gather together.Therefore,it is the place where traffic accidents occur frequently.Due to the special plane geometry characteristics of irregular signal intersections,the traffic operation situation is quite different from that of regular intersections,so there are more problems of traffic safety and operation efficiency that need to be paid attention to.Compared with traditional methods based on statistical accident data,the research method based on traffic collision technology has the advantages of large sample size,short period and easy access.At the same time,traffic simulation technology can be used to evaluate and study the traffic operation before and after the modification.Therefore,this paper explores the safety and efficiency characteristics of urban irregular signal intersection using traffic conflict technology and simulation modeling as the main means.Firstly,through the theoretical study of road traffic conflict,the connotation of the definition of traffic conflict is analyzed,and the definition of urban intersection traffic conflict is proposed.This paper further explores the classification of urban irregular intersections,and classifies urban irregular intersections into regular-irregular intersections and irregular-irregular intersections according to their different plane geometric characteristics,at the same time analyzes their traffic conflict characteristics.Secondly,based on the video data of the actual intersection traffic survey,the actual vehicle trajectory was obtained by using the video image processing technology.The method of calculating vehicle running state parameters and traffic flow parameters through trajectory coordinates is explored.Then,the micro simulation software VISSIM and indirect traffic safety analysis software SSAM are used to establish the traffic conflict model of urban irregular intersections.The parameters for the driving behavior of the model are calibrated by orthogonal test.The precision is satisfactory when the error rate is 0.0078<5%after calibration.Finally,based on signal optimization,this paper proposes a two-stage improvement method for intersection efficiency and safety.The first stage focuses on improving the operation efficiency of the intersection,mainly adopting phase overlap to solve the problem of uneven operation direction of the traffic flow at the intersection,so as to make full use of the effective green time of each phase and improve the operation efficiency of the intersection.The second stage mainly focuses on improving safety,and adopts the signal phase design to separate the conflicting traffic flows,thus greatly reducing the traffic conflicts in the intersections.An improved particle swarm optimization algorithm is used to determine the final optimal signal cycle length.Finally,the proposed signal phase scheme can significantly improve the traffic operation efficiency and reduce the intersection collision by 62%.Therefore,the two-stage improvement method of intersection efficiency and safety proposed in this paper is a new idea with strong practical significance and can provide reference for relevant departments of traffic management.