Research On The Safety Evaluation Of Urban Road Plane Intersection Based On Traffic Conflict Technique

Intersections are the bottlenecks and the accident black spot regions of city road network. It is very important for guaranteeing the travel safety of residents and the operating efficiency of city roads to reduce the occurrence rate of the accidents and to improve the safety of the intersection. Safety assessment of urban road intersections is an important content of improving intersection safety, and it’s also an important content in the field of urban road traffic safety evaluation. Meanwhile it has an important value for analyzing the cause and mechanism of intersection accidents and the safety design and operation management at city road intersection.Firstly, the research status and development trend of the traffic conflict in the plane intersection at domestic and abroad be analyzed in this paper. Domestic and foreign scholars tended to study the safety level of intersection from the traffic conflict based on the qualitative analysis of probability of traffic conflict be found in the paper. Secondly,the problems in the application of the intersection traffic conflict be summed up in this paper, including the types of conflict and collision angle were too short, the classification of dangerous conflict influence factors were not enough, the conflict degree of danger or risk degree calculation and evaluation factors were not comprehensive.Thirdly, the grey clustering evaluation principle be used in this paper to construct a traffic conflict technique of urban road intersection risk system based on the calculation model to calculate the different kinds of traffic conflict risk level at intersections.Model was constructed for the specific contents were as follows. Firstly, all traffic conflicts in urban road signalized intersection be divided in the paper as 5types :conflict between vehicles, conflict between vehicles and bicycles, conflict between motor vehicles and pedestrians, conflict between non motor vehicles, conflict between non motor vehicles and pedestrian. Six factors influence the risk of conflict degree be extracted in the paper, including conflicts category, avoiding space size,collision angle, conflict time, regional conflicts area, relative velocity of participants.Secondly, the paper determined 5 intervals range, which were not dangerous, minor danger, dangerous, very dangerous, extremely dangerous according to the actual survey and the model calculation. In this paper, the gray clustering assessment model were used to analyze the weight of each factor in the traffic conflict risk level. Then thecomprehensive risk degree of the traffic conflict was calculated according to the interval threshold of the risk degree. Thirdly, the five traffic conflict occurrence frequency in same period be analyzed and be calculated the degree of the overall risk for all traffic conflict in one cycle in order to judge the conflict degree risk in a period of time at intersection in the paper.The research results show that the urban road intersection safety evaluation method based on TCT not only could calculate the traffic conflict risk at intersections, but also compare traffic conflict security level in different periods. It has a great helpful on calculating the risk degree of intersections.This method is also convenient for horizontal comparison of traffic conflict risk in different planes. This model can predict the traffic conflict risk in the new intersection and predict the traffic risk level based on the distribution of different traffic flow in the new intersection.