基于电子不停车收费数据的山区高速公路 车速分布与车型分类研究

为研究山区高速公路车型分类方法，以重庆市包茂高速某路段的电子不停车收费数据(即ETC数据)为基础，分析平缓路段和连续上坡路段不同车型的速度分布特征发现：在不同线形路段，部分车型的速度分布有明显的特点，三型货车在连续上坡路段速度分布呈驼峰状，四型客车因营运限速的存在，在平缓路段速度分布集中于最大速度92 km·h-1 ；相同线形路段各车型速度分 布显著不同，客车车型在平缓路段速度分布表现为分散，在连续上坡路段相对集中，而货车车型的速度分布变化趋势正好相反；连续上坡路段各车型的速度特征值明显下降，但同路段上的部分车型间的速度特征值仍较为接近；连续上坡路段速度离散性大于平缓路段，追尾风险水平更高。在ETC数据基础上，运用k-medoids算法对山区高速公路平缓路段和连续上坡路段的车型进行聚类分析，优化后车型分类结果为：平缓路段车型可分为4类，分别为一型客车、二型～四型客车、一 型货车、二型～六型货车；连续上坡路段车型分类结果为4类，分别为一型～四型客车、一型货车和三型(空载)货车、二型～四型货车(三型为满载)、五型～六型货车。本文有助于山区高速公路速度管理措施的制定和道路线形设计时代表性车型的选择。

Speed Distribution and Vehicle Type Classification of Mountain Expressway Based on Electronic Toll Collection Data

In order to study the classification method of mountain expressway vehicles, based on the electronic toll collection data (ETC data) of a section of Baomao expressway in Chongqing, the speed distribution characteristics of different vehicles in gentle sections and continuous uphill sections are analyzed. The speed distribution of some vehicles in different linear sections has obvious characteristics, the speed distribution of type-3 trucks on continuous uphill sections is hump-shaped due to the existence of the speed limit for type-4 passenger cars, and the speed distribution in gentle sections is concentrated on the maximum speed of 92 km· h-1 . The speed distribution of different vehicles in a linear section is obviously different, and the speed distribution of passenger cars is scattered in the gentle sections yet relatively concentrated in the continuous uphill section, whereas the speed distribution of trucks is different; the speed eigenvalues of each vehicle on the continuous uphill section have decreased significantly, but the speed eigenvalues of some vehicles on the same road section are still relatively close. The speed dispersion of continuous uphill sections is greater than that of gentle sections, and the risk of rear-end collision is higher. Based onthe ETC data, the k-medoids algorithm is used to perform a cluster analysis on the vehicles in the gentle section and the continuous uphill section of the mountain expressway. The gentle section vehicles can be divided into 4 categories, including type-1 passenger cars, type-2 to type-4 passenger cars, type-1 trucks, and type-2 to type-6 trucks. The vehicles can also be classified into 4 categories in continuous uphill sections, including type-1 to type-4 passenger cars, type-1 and type-3 trucks without load, type-2 trucks, type-4 trucks, type-3 trucks with a full load, and type-5 and type6 trucks. This study is helpful for the formulation of speed management measures for mountainous expressways and the selection of representative vehicle types in road alignment design.