School of Highway, Chang'an University, Xi'an, China.
School of Highway, Chang'an University, China.
Accid Anal Prev. 2021 Mar;152:105960. doi: 10.1016/j.aap.2020.105960. Epub 2021 Feb 2.
High crash rates on horizontal curves during wet weather are a major road safety concern. Among the various causes of crashes on horizontal curves, wet-weather skidding is a major contributing factor. This study analyzed the mechanisms of three possible modes of vehicle skidding on horizontal curves based on theories of mechanics. The three modes of skidding analyzed were: (i) forward skidding of front steering wheel, (ii) sideway skidding of front steering wheel, and (iii) sideway skidding of rear wheel. The main objective was to provide useful information to researchers and practitioners in identifying the important factors that contribute to horizontal curve crashes. A computer simulation procedure was developed to evaluate the maximum safe vehicle speeds against the three modes of skidding on wet horizontal curved pavements. This offers a much improved method for skidding potential evaluation compared to the conventional approximate method using estimated coefficient of friction. The skidding potential of a vehicle is defined as the difference between its speed and the maximum safe speed against skidding. The smaller the difference, the higher is the skidding potential. The relative magnitudes of skidding potential for the three skidding modes were considered for different operating conditions. Different operating conditions were represented by different values of pavement curve radii, super-elevations, and wet-weather conditions represented by the thickness of pavement surface water-film. The analysis identified five key factors that affect the skidding potential of vehicles negotiating a horizontal curve. They are: vehicle speed, curve radius, superelevation, water film thickness and pavement skid resistance state.
在潮湿天气下，车辆在水平曲线路段的碰撞率较高，这是道路安全的一个主要关注点。在导致水平曲线碰撞的各种原因中，湿滑是一个主要因素。本研究基于力学理论，分析了车辆在水平曲线路段可能发生的三种打滑模式的机理。分析的三种打滑模式为：（i）前轮转向时的前滑，（ii）前轮转向时的侧滑，以及（iii）后轮侧滑。主要目的是为研究人员和从业人员提供有用的信息，以识别导致水平曲线碰撞的重要因素。开发了一种计算机模拟程序，以评估在湿滑水平曲线路面三种打滑模式下的最大安全车辆速度。与使用估计摩擦系数的传统近似方法相比，这提供了一种改进的打滑潜力评估方法。车辆的打滑潜力定义为其速度与最大安全打滑速度之间的差值。差值越小，打滑潜力越高。考虑了三种打滑模式在不同运行条件下的打滑潜力的相对大小。不同的运行条件由不同的路面曲线半径、超高值以及路面表面水膜厚度表示的湿滑条件来表示。分析确定了影响车辆在水平曲线路段行驶时打滑潜力的五个关键因素。它们是：车辆速度、曲线半径、超高值、水膜厚度和路面防滑状态。
