环形交叉口评价指标选取及服务水平分级

Evaluation Indexes Selection and Level-of-service Classification for Roundabouts

对环形交叉口的车辆运行特性进行理论分析的基础上,结合不同类型交叉口的特点,确定了车辆平均延误和冲突数作为环形交叉口服务水平的评价指标,接着通过VISSIM软件仿真得到了环形交叉口两个指标随V/C增加的变化规律,从而确定低负荷下采用车辆平均延误作为主要评价指标,高负荷下采用冲突数作为主要评价指标,最后,借鉴HCM2000的分级标准对2车道4肢环形交叉口的服务水平进行了分级,为环形交叉口的性能评价和改进方案优选提供理论依据。

Based on theoretical analyzing the traffic operation performances at roundabouts and consided the features of different types of intersection,average stop delay and number of conflicts were determined as the indexes to evaluate the level of service at roundabouts.Then,the regularity of the two evaluation indexes varying with V/C was obtained with help of VISSIM simulation software.After prudent analysis,it is determined that to take average stop delay as the primary evaluation index when V/C is low and to take number of conflicts as the main evaluation index when V/C is high.At the end,the level of service at two-lane four-leg roundabout intersections was classified by using HCM2000 Classification Standard as reference,which provides a theoretical basis for performance evaluation and improvement optimization for roundabouts.