城市道路车辆分类及折算系数研究

城市道路上交通构成复杂,对交通流进行研究时希望能够有一个统一的标准来计量道路上行驶的车辆。车辆折算系数是指将混合车流中的各种车型转化成标准车的当量值,是道路规划与设计中的重要指标之一。由于该系数在不同地点和时间的交通流状况下不尽相同,就需要一种调查简单而结果又合理的计算方法。从定义各类型车辆所占用的动态空间瞬时车道占有率入手,提出了以车辆瞬时占用车道长度与速度的比值为参数,基于模糊动态聚类对车辆进行分类的方法。并利用该方法对城市主干路上的交通调查数据进行了计算,将车辆进行合理的分类,并根据最佳分类的聚类中心值给出了城市道路上的车辆折算系数,最后分析了城市道路上各种车辆折算系数的特点。

A Study on Vehicle Classifications of Urban Road and Their Conversion Factors

The composition of urban traffic is rather complex. To analyze the mixed traffic volumes, a unified standard for calculating vehicular volumes is needed. Vehicle conversion factor is an important parameter in road planning and design. There is a need to establish a simplified and yet reasonable methods to get different types of vehicles converted into an equivalent unit under different traffic conditions. The paper analyzes the characteristics of fuzziness of dynamic space occupancy of different vehicles on urban arterials, and classifies the different vehicles by means of fuzzy clustering. The instant vehicular occupancy and speed are taken into consideration in determining vehicle conversion factors. Finally, the paper proposes a set of vehicle conversion factors based on a fuzzy clustering method.