Research On Pedestrian-Right Turn Vehicle Conflict Risks And Crossing Decisions At Intersection Based On Trajectories And Value Of Time

With the increasing shortage of road resources and improper traffic control measures,urban road intersections are urban road nodes and major traffic bottlenecks,and pedestrians,non-motor vehicles and motor vehicles have very fierce competition and traffic conflicts at urban road intersections.At most intersections on urban roads in our country,the red light allows right motor vehicles to pass through RTOR(Right Turn On Red).There are a lot of conflicts between right-turning motor vehicles and pedestrians crossing the street,which seriously reduces the efficiency of intersection traffic,and even leads to traffic congestion in the case of rushing.Accidents happen.Carrying out research on the risk of crossing conflicts between pedestrians and right-turning motor vehicles and crossing decisions is of great significance for improving the safety and overall operating efficiency of urban roads.Therefore,this paper studies the mathematical modeling of right-turn maneuver trajectory,pedestrianright-turn vehicle conflict risk assessment,pedestrian-right-turn vehicle conflict crossing decision-making,and related improvement measures for the problem of pedestrian-right-turn vehicle conflict crossing at intersections.First of all,after deep analysis of the characteristics of pedestrian-right turn traffic conflicts at urban road intersections in our country,based on the aerial video data of multiple intersections,a vehicle recognition and tracking system based on YOLOv5 and Deep SORT was built,and with the use of George and Tracker video analysis software,carry out characteristic research on the trajectories of right-turn vehicles at intersections,and obtain the influencing factors of trajectories in both cases with and without interference,and proposed that trajectories are dynamically distributed in three-dimensional space,and conduct deep research on the dynamic process of trajectory arrangement.Using curve fitting,parameter regression and other methods carried out mathematical modeling of turning vehicle trajectories at intersections,the transformation of trajectories from individual to whole at different intersection entrances is realized,and the mathematical models of trajectories under two conditions of presence and absence of interference are established.Verified the prediction error of the model for the trajectory.Secondly,starting from the physical structural characteristics of the vehicle,the motor vehicle is divided into four parts based on the Driv Aer model of vehicle aerodynamics.Considering the possibility and severity of conflicts between different parts of the vehicle and pedestrians crossing the street,the front of the vehicle is drawn separately.,rear wheels and inner and outer wheel trajectories,combined with the comparison and analysis of safety risk differences in different positions of the vehicle physical structure,from the perspective of trajectory difference,it can be concluded that the collision risk of the inner wheel is higher than that of the outer front wheel in the pedestrian-right turn collision process,and the inner wheel The risk of conflict between the front wheels is higher than that of the rear wheels.The trajectory function model of the inner front wheel and the inner rear wheel is constructed,and the traffic characteristic parameters of the two types of inner and outer wheel trajectories are compared and analyzed,and the accuracy of the trajectory model is verified by fitting with the observed trajectory.Thirdly,in order to effectively evaluate the conflict risk of pedestrians and right-turning vehicles,a pedestrian-right-turning vehicle conflict evaluation framework under different interaction modes of pedestrian-vehicle conflicts is introduced.Conflict events are classified into three interaction modes: "hard interaction","no interaction" and "soft interaction".Using the support vector machine(Support Vector Machine,SVM)algorithm,the risk severity classification and variable importance analysis were carried out on the extracted data sets of conflict events.And according to the contribution of the conflicting indicators to the evaluation of the risk degree,the aggregation of the weighted indicators in each interaction mode is completed.According to the conflict index TTC,PET and other time values,the conflict events in each interaction mode are divided into three types of risk severity,which are represented by the risk levels I,II,and III respectively,and the conflict risk assessment system between pedestrians and right-turning motor vehicles is constructed.Then,based on the acceptable gap theory of pedestrians and the user value of time(Value of Time,VOT),combined with the actual situation,from the perspective of pedestrians and motor vehicles,the conflict game between pedestrians and right-turn vehicles intersections was studied.The acceptable gap theory of motor vehicles and pedestrians rushing out of the waiting time and the game theory model of different payment utility determined by their VOT,according to the different VOT of pedestrians and right-turn vehicles and when the conflict occurs determined the probability of pedestrians rushing to cross the street under different waiting times,and the utility payment function parameter values of pedestrians and right-turn vehicles when they take different decisions.According to the payment utility function,the final function value can be calculated.Drawing the game tree model to obtain the optimal solution of the game crossing.Get the best decision-making scheme for the crossing process.Finally,taking the Nanshaomen intersection in Xi’an as an example,combined with the existing problems of the intersection,the risk of conflict between pedestrians and right-turn vehicles at the intersection was evaluated,and the risk severity based on the SVM classification algorithm in different interaction modes was determined.By VISSIM simulation,the speed of right-turn vehicles,turning delays,queuing,and conflicts between people and vehicles were obtained,and based on trajectory extraction and the distribution of conflict areas,improvement measures for intersections were proposed.