信号控制交叉口货车折算系数研究

Study on Passenger Car Equivalency for Heavy Vehicles at Signalized Intersections

从货车对车队消散影响角度建立了信号交叉口排队车辆车头时距模型并推导了货车折算系数公式,以VISSIM为仿真平台探讨了货车混入比例及服务水平与折算系数的关系。结果表明:货车为首车时折算系数最大,随着排队位置的后移而逐渐减小,随着队列消散趋于稳定而趋于稳定;当在货车混入比例在30%以下时,折算系数随着混入比例的上升明显下降,货车混入比例大于30%之后,交通流更加匀质,折算系数趋于稳定;且当延误较低时,车型折算系数没有实际意义,延误较高时,可采用统一的车型折算系数。

The formula which has considered the additional headway caused by heavy vehicles in different queue positions has be derived.Then analyze the impact of percentage of heavy vehicles and LOS on PCE based on the VISSIM simulation platform.The calculated results show that the maximum PCE belongs to the vehicle in the leading position,and the value of PCE decreases with the queue position become larger,and tends to be stable with the queue discharge tending to be stable.When the percentage of heavy vehicles is below 30%,PCE decreases with the percentage increasing,and when the percentage of heavy vehicles is above 30%,the traffic stream become more homogeneous and PCE tends to be stable.PCE has no practical sense when the delay is low,and a set of uniform PCE can be adopted when the delay is high.