Abstract: The passenger-car equivalents theory and methodology of urban expressway merging area afflux car was discussed. Based on measured data of Shanghai expressway and from the analysis of process of ramp vehicles merging mainline, considering varies influencing factors about vehicles merging mainline, such as length of car bodies, vehicle performance and time headway distribution of vehicles of outer lane in mainline of various models, afflux car passenger-car equivalents models were established and the suggested values of afflux car PCE in two afflux modes were provided, according to ramp merging capacity of various models of vehicles, sufficiently accelerated afflux mode and parking afflux mode. The conclusion indicates that afflux car PCE have much to do with afflux modes of ramp vehicles and vehicles volume of outer lane in mainline, PCE and the main line outside lane traffic is correlated; at the same rate of outside lane, the PCE of sufficiently accelerated afflux mode is less than parking afflux mode. In calculating, the ramp merge area capacity should not simply take a certain value of PCE to afflux car

Key words: traffic engineering;urban expressway, ramp merging area, vehicle conversion coefficients, marginal gap, traffic capacity

摘要： 讨论了城市快速路匝道合流区汇入车辆的车辆折算系数（PCE）计算的理论和方法。基于上海市快速路实测数据，从匝道车辆汇入主线的过程分析出发，考虑各类车型车身长度、车辆 性能和主线外侧车道车头时距分布等因素对车辆汇入主线的影响，根据间隙接受理论和不同主线流量下各类车型的匝道汇入能力，建立了匝道合流区汇入车辆折算系数模型，并给出了在充分 加速汇入和停车汇入两种汇入模式下PCE的建议值。研究表明：PCE值与汇入模式和主线外侧车道流量有很大关系，其与主线外侧车道流量呈正相关性，在同等主线外侧车道流量下，充分加速 模式较停车汇入模式的PCE值小；在计算匝道合流区通行能力时不应对汇入车辆的PCE简单的取一定值。

关键词: 交通工程, 城市快速路, 匝道合流区, 车辆折算系数, 临界间隙, 通行能力