基于头车疏解车距的混合交通信号交叉口通行能力研究

Capacity Analysis of Signalized Intersections under Mixed Traffic Conditions Based on the First Discharge Headway

头车疏解车距(The First Discharge Headway)是绿灯开始后到第一辆机动车启动并通过停车线的时间.本文分析了混合交通信号交叉口不同车道交通流的车型比例和干扰比例,结果表明,左转车道的小型车比例和受到的干扰次数高于直行车道.随后利用Logistic模型、Compertz模型、Logsitic模型分别对左转车道、内侧直行车道、外侧直行车道的头车疏解车距进行拟合,用Matlab软件对头车疏解车距累计频率15%至85%之间的数据进行定积分运算,得到各车道的修正头车疏解车距分别为3.98 s,4.60 s,4.85 s.最后通过实例验证,发现对于不同车道,模型修正后的误差比模型修正前都有明显的下降.

The First Discharge Headway is the time consumed by the first car in the queue from its startup when the green light turns on to the second while it is completely across the stop line.This study analyzes the traffic composition and interference ratio of different lanes at the signalized intersection with mixed types of traffic flows.It is presented that left-turning lanes holds more small-sized vehicles and have much more interference.The functions of the first discharge headway of the left-turning lanes,inside through lanes,and outside through lanes are respectively studied by the Logistic model,the Compertz model and the Logsitic model.By further calculation,the first discharge headways of the left-turning lanes,inside through lanes,and outside through lanes are 3.98s,4.60s and 4.85s respectively.The errors of modified model and the traditional one are computed by using the actual data.It turns out that the error of the modified model decreases sharply in comparison to the error of the traditional model.