Methods Of Crosswalk Setting At Two Phases T-intersection Accounting For Traffic Efficiency And Safety

The T-intersection of two phases is an important part of urban road network,whereas the main road pedestrians and left-turning vehicles of branch share a phase.During the time of the phase,the pedestrian flow and the left-turning vehicle flow compete for the road resources at the crosswalk,which results in interferences,reduces the traffic efficiency and increases the crash risk of the intersection.Based on traffic efficiency and safety,the author studies the optimal arrangement of crosswalks setting.Passengers' delay is an important index to evaluate traffic efficiency of intersections.According to the two situations results of before and after the setting of the crosswalk,the author establishes a model to calculate the per capita delay of the affected population and through the comparison and analysis,then gets the critical condition about setting the crosswalk.Traffic conflict technique is widely used for traffic safety analysis in recent years.In this paper,post-encroachment time(PET)is used as the index to quantify the severity of the conflict during the analysis process.The author divides the pedestrian-vehicle conflicts into three levels(ig.,potential,slight,and serious conflicts)according to the PET values and analysis the influence factors of the severity of the conflict using the correlation analysis method.Then the author establishes the quantity model of pedestrian-vehicle conflict in the scenarios of intersection with two crosswalks and that with three crosswalks,respectively.The threshold of the volume from models to determine the number of crosswalks which should be equipped at the T-intersection is found in this paper.Finally,the author establishes the Performance Index model of the intersection considering both traffic efficiency and safety.Then by taking a T-intersection of two phases in Chengdu for an example,the author calculates the per capita delay of the affected population and the number of conflicts between pedestrians and vehicles,and gets the optimal arrangement of crosswalks setting.