Research On Right Turning Vehicle-Pedestrian Conflict Model And Traffic Safety Design Method At Signalized Intersections

Approximately 1.3 million people die in road traffic accidents every year,with about half of the world’s road traffic fatalities being "vulnerable road users," including pedestrians,cyclists,and motorcyclists.Due to the high incidence of pedestrian accidents at intersections and the vulnerable position of pedestrians,an increasing number of researchers are focusing on pedestrian safety issues.Traditional safety analysis methods rely on collision data as a data source,but alternative safety measures represented by traffic conflict theory and technology have rapidly developed in recent years due to constraints on the completeness and accuracy of collision data.These measures have formed a relatively complete framework,but the theoretical system and application methods still require further research.Firstly,this study investigated the conflict data between right-turning vehicles and pedestrians at three signalized intersections,as the basis for data analysis.The secondary conflicts of right-turning vehicles were classified as either primary or secondary,and multiple angles of safety evaluation indicators were used,including the distance-velocity framework(DV framework),post-encroachment time(PET),maximum rejection gap,acceptance gap,critical gap,average crossing vehicle speed,and special conflicts.Statistical tests and box plots were used to analyze the safety of pedestrian crossing during the second conflict of rightturning vehicles and to draw conclusions on the significant differences in pedestrian crossing safety between primary and secondary conflicts.Secondly,the limitations of using the widely used traffic conflict indicators,such as time to collision(TTC)and PET,in analyzing pedestrian-vehicle conflicts were analyzed.At the same time,the shortcomings of using time advantage(TAdv)and similar indicators in analyzing pedestrian-vehicle conflicts were also analyzed.Based on this,a new type of traffic conflict indicator called Improved TAdv was proposed to identify pedestrian-vehicle conflicts that do not involve collision trajectories.Using TTC,PET,and Improved TAdv to identify and analyze conflicts between right-turning vehicles and pedestrians at signalized intersections,factors such as conflict type,pedestrian characteristics(gender,age),pedestrian behavior(crossing direction,crossing speed,pedestrian group size),traffic flow characteristics(pedestrian volume,right-turning vehicle volume),and vehicle characteristics(vehicle type and approaching speed)were taken into account to construct a model of conflicts between rightturning vehicles and pedestrians at signalized intersections,and to analyze the impact of each influencing factor on the probability of conflicts between right-turning vehicles and pedestrians.Finally,the article analyzes the limitations of the basic assumptions of the DV framework and proposes an improved DV framework based on the analysis of vehicle speed.Based on the requirements of the improved DV framework for the driver perspective,a stepped stop line design is proposed.Using the K-means clustering method to cluster the vehicle speed,a model for the primary conflict between right-turning vehicles and pedestrians is constructed to explore the method of setting speed bumps in the right-turn lane.