Research On Safety Evaluation Method Of Urban Expressway Weaving Area Based On Traffic Conflict Prediction Model

Urban expressway,which is the main part of whole urban road network,can effectively alleviate urban traffic pressure and improve travel efficiency.In the weaving section of expressway,the time of vehicle merging and shunting is short,and there are a large number of lane changing or weaving behaviors,resulting in large dispersion of vehicle speed and many traffic conflicts and accidents.The urban expressway weaving area is the research object.The traffic conflict technology is taken as the study method to discuss the traffic safety evaluation of the expressway weaving area.Establishment of the traffic conflict prediction model and the safety evaluation method of the expressway weaving area are the research goal.The traffic conflict in the expressway weaving area and the formation process are defined.Through field investigation,the geometric design parameters,traffic flow operation parameters and traffic conflict characteristic parameters of expressway weaving area are collected,the characteristics of traffic flow and traffic conflict are explained.In addition,the TTC threshold for judging the severity of traffic conflict is determined.Based on the survey data,the simulation orthogonal experiments are carried out.The traffic conflict data under different operation conditions are obtained,and the negative binomial prediction models of traffic conflict are established.Based on different types of traffic conflicts and different severity of traffic conflicts,the safety evaluation indexes of expressway weaving area are established.The traffic safety level thresholds of expressway weaving area are determined by grey clustering method,and the traffic safety evaluation flow chart of expressway weaving area is drawn.The prediction models of side attack conflict,rear end conflict,general conflict and serious conflict are established,which can be applied to conflict prediction of the expressway weaving area.Meanwhile,establishment of the traffic conflict risk indexes based on different types and severity are completed,which means the accuracy of traffic safety evaluation indexes are improved.