Traffic Safety Assessment Method Of Merge Area Based On The Traffic Conflict

The merge area of highway interchanges is often an accident-prone area due to its diverse structures and complex traffic flow environment.Therefore,it is necessary to grasp the law of traffic flow,find out the prominent factors that affect the traffic safety,carry out traffic safety evaluation systematically,and put forward targeted traffic safety promotion strategies.In order to avoid the inherent shortcomings of traffic accident data,this paper used the traffic conflict technology to analyze the formation mechanism and influencing factors of the traffic conflicts in the merge area,constructed the traffic conflict prediction model and formed the traffic safety evaluation method.First of all,based on the purpose of the study and the current investigation condition,the Ma Qun interchange and Lin Dong interchange were selected as the investigation objects.Manual survey and UAV aerial were used to get the traffic flow data.The observation of traffic conflicts as well as the identification of TTC thresholds of different types of traffic conflicts were conducted by means of objective observation combined with subjective observation.Based on the data,the law of the traffic flow in the merge area is explored.Furthermore,the formation mechanism and conflict distribution characteristics of traffic conflicts were analyzed,and the relationship between the influencing factors and traffic conflicts was analyzed preliminarily.In order to construct the traffic conflict prediction model,VISSIM software was used to simulate the traffic flow under different geometric conditions and traffic flow conditions to get the trail file and the evaluation file of the section.Then,SSAM software was used to obtain different traffic conflict data by processing the trail file VISSIM simulated.Based on the correlation between each factor and traffic conflict,the factors with significant correlation were selected as independent variables,and the traffic conflict prediction model was constructed by regression analysis.Then,the model is validated by the measured data.The results showed the model was of high accuracy and practicality.Finally,taking the traffic conflict rate and the conflict density as the evaluation index,the gray level clustering model was used to divide the traffic safety in the merge area into four grades,and the criteria of each level were also identified.Based on the traffic flow indicators under each safety level,the traffic flow characteristics and traffic safety characteristics of each grade were described qualitatively.Based on the analysis of the traffic flow and the distribution characteristics of traffic conflicts at different safety levels,the paper put forward targeted strategies to improve traffic safety performance.