典型信号控制交叉口行人专用相位设置阈值研究

针对目前城市道路交叉口中人车混行现象,综合考虑效率与安全两方面因素,选取延误成本和冲突成本分别作为效率与安全的评价指标,构建有(无)行人专用相位信号控制模式的交叉口运行成本模型.模型的延误成本中,行人和非机动车延误考虑了信号延误、冲突延误以及绕行延误;冲突成本则基于交通冲突理论,以车头时距判断机动车与行人和非机动车是否发生冲突为指标,并根据机动车及行人和非机动车达到分布确定冲突概率.最后,通过北京市四道口交叉口验证了该模型的适用性,并基于遗传算法求得典型信号控制交叉口中行人专用相位设置的阈值在750~900人/h浮动,随着车流量的增长,行人专用相位的设置对行人流量的要求呈现先降后升的趋势.为城市道路交叉口信号配时设计提供了理论支撑,保障行人及非机动车安全、舒适、方便、尊严的出行. 

A Study on Threshold of Exclusive Pedestrian Phase for Typical Signalized Intersections

Pedestrian-vehicle mixed in urban intersections is common and has negative effects on efficiency and safety of intersections.A cost model of intersection operations with or without exclusive phase signal for pedestrians is developed using delay cost and conflict cost as evaluation indices.Signal delay, conflict delay, and detour delay are all considered to calculate delay cost of pedestrians and non-motor vehicles.As for the conflict cost, based on traffic conflict theory, time headway is used to judge whether motor vehicles have conflicts with pedestrians or non-motor vehicles.Conflict possibility can be determined by arrival distribution of vehicles and pedestrians.The Sidaokou intersection in Beijing is chosen as a case study.Based on the collected data and genetic algorithm, the threshold of pedestrian flow is 750-900 ped/h for setting exclusive phase for pedestrians.With the increase of traffic flow, the requirement of pedestrian flow is descending at first, and then ascending at last.This study can provide a theoretical support for signal setting of urban intersections, and improve safety and convenience for pedestrians and non-motor vehicles.