Traffic Safety Risk Assessment Method For Signalized At-grade Intersection

AT-grade intersections are important parts of the road network,which are often the “bottleneck” areas of the road traffic system.There are also traffic accidents frequently occurrenced,as well as high risk of traffic safety.Therefore,in order to reduce traffic accidents and their losses,to improve the traffic safety management level of at-grade intersections,it’s necessary to analyze and study the traffic safety risk generated at the at-grade intersections.In this paper,the signalized at-grade intersection had been taken as the research object,and on the basis of summarizing the research status of traffic safety risk and traffic safety risk assessment,the concept of traffic safety risk of signalized at-grade intersection had been defined,and the research idea of traffic safety risk assessment of signalized at-grade intersection based on traffic conflict analysis had been proposed.Based on an analysis of traffic conflicts between motor vehicles,non-motor vehicles and pedestrians,five types of traffic safety risks of the signalized at-grade intersections have been classified.The traffic safety risk assessment model and prediction model of the signalized at-grade intersection had been then established,to provide the corresponding theoretical supports for the quantitative assessment of traffic safety risks,as well as the effect analysis of traffic safety risk control measures for the signalized at-grade intersection.Firstly,the video observation method had been used to obtain the traffic conflict data,the characteristics of the mixed traffic in the signalized at-grade intersection have been studied.By means of the traffic conflict analysis chart,the different types of traffic conflicts in the signalized at-grade intersection had been analyzed.Based on probability theory,traffic flow theory and traffic conflict theory,and with the number traffic conflicts and the severity of traffic conflicts as the model parameters,the traffic safety risk assessment model for the signalized at-grade intersection had been established.By combining subjective method with objective analysis,the weight of different types of traffic safety risks had been assigned.Secondly,with the combination of gray theory and Markov theory,the traffic safety risk prediction moed for signalized at-grade intersection had been established and verified,to predict the degree of traffic safety risk and its corresponding level in the specific time period,in order to help the analysis and determination of the traffic safety risk control measures.Finally,the traffic safety risk assessment model for the signalized at-grade intersection had been applied,to assess and analyze the traffic safety risk of the sampled intersection,and to determine its traffic safety risk level.The gray markov model had been applied to predict the traffic safety risk level.Based on the assessment and prediction results,the traffic safety risk control measures of signal-controlled intersection had been analyzed and then determined.