Study On Traffic Conflicts Based On Surrogate Safety Assessment Model

In this paper, urban intersection for the study, intended to traffic safety perspective, a traffic safety evaluation method was proposed through microscopic traffic simulation technology combined with traffic conflict, improving the accuracy and efficiency of traffic safety assessment. Also scientifically and effectively analyze the traffic safety situation of intersection, to find concrete measures to improve safety degrees at intersections and provide reference for the transportation design and planning manager.Firstly this paper introduced the principle, function and applicability of micro-simulation model and analyzed the basic principles of Surrogate Safety Assessment Model(SSAM) to identify the conflict, also summarized related evaluation index of intersection traffic safety evaluation based on traffic conflict techniques. On this basis microscopic simulation model of intersections were established, and then usign SSAM to analysis trajectory file output by simulation model to obtain conflict data. A comprehensive safety evaluation model for traffic facilities was established by vehicle conflict indexes and traffic efficiency evaluation indicators, including average delay, queue length and the number of stops. By modifying the micro-simulation model parameters, determine the impact factors of the traffic intersection conflict, including the traffic flow, vehicle composition, and the proportion of vehicle left and the distribution ratio of intersection traffic flow.In this paper, three different types of intersections, including crossroad, roundabout and Y-intersection, evaluation model based on microscopic traffic simulation models and conflict techniques were established, for traffic safety evaluation study. According to the intersection field survey of traffic accident data, the validity and applicability of evaluation methods based on SSAM were examined.The results show that the traffic safety evaluation method of microscopic simulation combined with traffic conflicts technology can evaluate the various forms of intersection traffic safety situation more effectively and efficiently, and noted the traffic safety factors of intersections. Improvement measures were proposed to reduce conflict and improve traffic safety, providing reference for improving the intersections.