基于速度变化量的车辆折算系数研究

车辆折算系数是道路通行能力计算和服务水平评价等方面最重要的基础参数之一。通过对基于密度相等的方法、时距法和超车法进行了介绍和分析,提出了以车辆速度变化量为基础的车辆当量折算系数,分析了影响车辆折算系数的因素;并分别选取了不同车道数、不同坡度、不同服务水平以及不同大车比例。通过微观仿真平台验证了不同组合交通情况下的车辆当量折算系数及折算系数的变化趋势。结果表明:从1车道到2车道,折算系数增加,从2车道到3车道,折算系数出现了减小的趋势;在下坡路段折算系数比上坡路段大;随着流量的增加,折算系数先增加后减小;随着大车比例增加,折算系数出现增加的趋势。

Research of the passenger car equivalents based on the speed variation

s: The passenger car equivalent is basic parameter in road capacity calculation and level of service evaluation. The density method, headway method and overtaking method were analyzed firstly. Then the passenger car equivalent based on speed variation was given. Choosing the impact factors, the passenger car equivalent was calculation using micro-simulation software under different lanes, different grade, different bus ratio and different saturation. It is proved that the passenger car equivalent for the bus was increased from 1 lane changed to 2 lane, but decreased from 2 lane to 3 lane; and the value is bigger when the grade is downhill then uphill, with the traffic flow increased, the value is increased then decreased, moreover, the passenger car equivalent was increased with the ratio of bus increased.