定义了疏解车距(FDH)并分析了影响疏解车距的3种要素,通过实地调查获得的数据,标定疏解车距的分布函数.提出等效疏解车距的概念,并利用等效疏解车距计算直行车道的通行能力.在此基础上,分析了混合交通条件下,行人、非机动车的干扰对通行能力的影响.结果表明:疏解车距仅与车型及干扰因素相关,且两者之间不存在交互影响;Weibull分布可以较好地描述疏解车距的累积概率分布;应用等效疏解车距对直行车道的通行能力计算方法进行修正后,计算通行能力与实际通行能力之间的误差在5%以内;随着行人和非机动车对机动车冲突频次的增加,通行能力呈现指数型递减,冲突的影响存在边际效应.
This paper presents a new approach for calculating straight lane capacity under mixed traffic conditions,especially in China.The First Discharge Headway(FDH) is applied as a novel to improve stop line method model,and the influencing factors of FDH are analyzed.To calibrate the FDH probability distribution,investigation data of four intersections in Beijing are employed.The Equivalent First Discharge Headway(EFDH) is proposed to replace the current empirical value in traffic capacity calculation.Using the improved model,the paper analyzes conflicting pedestrian and non-motor volumes' impact on capacity under mixed traffic conditions.The results show that FDH is only related to vehicle type and external disturbance factors(α0.05),and there is no mutual influence between each other.The Weibull distribution could well be applied to describe the probability distribution of the FDH.Though the EFDH correction,the calculation error of capacity is reduced to less than 5%.The traffic capacity presents exponential decline with the increase of conflict frequency between pedestrians,non-motors and motorized vehicles,the conflict influence is diminishing marginal utility.