Study On Evaluation Method Of Urban Intersection Traffic Safety Based On Traffic Conflict Technique

The application of micro simulation and traffic conflict technology in the traffic safety assessment of urban intersection could improve the efficiency of the evaluation process and analysis how the factors influence traffic safety. It makes great significance for improving the traffic safety of urban intersection.First of all, reviewing the evaluation method of urban intersection traffic safety based on traffic conflict technique, a new evaluation model of urban intersection traffic safety is put forward. The risk degree of intersection is set as evaluation index. The traffic conflict data is obtained by the simulation technology.The evaluation model of urban intersection traffic safety consists of the risk of conflict between vehicle and vehicle, the risk of conflict between vehicle and non-motor vehicle, the risk of conflict between vehicle and pedestrian. The risk of each type conflict is obtained by stacking the risk of each traffic conflict. The risk of each traffic conflict is calculated by the risk degree model of traffic conflict. The risk degree model of traffic conflict is established by the factors of TTC, the conflict speed and the conflict angle.Considering the factors of vehicle dynamics, driving behavior, traffic flow, signal control parameters and intersection geometric parameters, vehicle trajectory is obtained. Using TTC as the conflict identification parameter to analyze the vehicle trajectory, the conflict type, conflict number, conflict time, conflict speed and conflict angle are calculated.Then, in order to study the influence of each factor to the model, the calibration and sensitivity analysis of the parameters are carried out. Based on analyzing vehicle starting delay, the value of vehicle starting delay is calibrated by the experiment. Based on the sensitivity analysis of traffic flow parameters, its influence on the safety of urban intersection is researched.Finally, based on the survey date, evaluation method of urban intersection traffic safety is applied to two intersection of Xi’an city. With the evaluation and analysis results, the measure of improving intersection traffic safety is put forward. The traffic safety before and after improvement is comparatively analyzed. The results show that the evaluation method of urban intersection traffic safety could be used to evaluate the traffic safety of intersection, and the analysis and evaluation of the results could be used as the basis for the improvement of intersection traffic safety.