Center for Transportation Research, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia.
Accid Anal Prev. 2011 May;43(3):1068-73. doi: 10.1016/j.aap.2010.12.013. Epub 2011 Jan 15.
Most highly motorized countries in the world have implemented different speed limits for light weight and heavy weight vehicles. The heavy vehicle speed limit is usually chosen to be lower than that of passenger cars due to the difficulty for the drivers to safely maneuver the heavy vehicle at high speed and greater impact during a crash. However, in many cases, the speed limit for heavy vehicle is set by only considering the vehicle size or category, mostly due to simplicity in enforcement. In this study, traffic and vehicular data for all vehicle types were collected using a weigh-in-motion system installed at Federal Route 54 in Malaysia. The first finding from the data showed that the weight variation for each vehicle category is considerable. Therefore, the effect of gross vehicle weight (GVW) and category of heavy vehicle on free flow speed and their interaction were analyzed using statistical techniques. Empirical analysis results showed that statistically for each type of heavy vehicle, there was a significant relationship between free flow speed of a heavy vehicle and GVW. Specifically, the results suggest that the mean and variance of free flow speed decrease with an increase GVW by the amount unrelated to size and shape for all GVW range. Then, based on the 85th percentile principle, the study proposed a new concept for setting the speed limit for heavy vehicle by incorporating GVW where a different speed limit is imposed to the heavy vehicle, not only based on vehicle classification, but also according to its GVW.
世界上大多数机动化程度较高的国家都对轻型和重型车辆实施了不同的限速。由于驾驶员在高速下安全操纵重型车辆的难度较大，且在发生碰撞时造成的影响更大，因此重型车辆的限速通常低于乘用车。然而，在许多情况下，重型车辆的限速仅考虑车辆尺寸或类别来设定，这主要是因为执行起来比较简单。在本研究中，使用安装在马来西亚联邦公路 54 号的动态称重系统收集了所有车辆类型的交通和车辆数据。从数据中得出的第一个发现是，每个车辆类别的重量变化相当大。因此，使用统计技术分析了总重（GVW）和重型车辆类别对自由流速度的影响及其相互作用。实证分析结果表明，对于每种重型车辆，重型车辆的自由流速度与 GVW 之间存在显著关系。具体而言，结果表明，在所有 GVW 范围内，重型车辆的自由流速度的均值和方差随着 GVW 的增加而减小，而与尺寸和形状无关。然后，基于 85%分位数原理，该研究提出了一个新的概念，即通过结合 GVW 来为重型车辆设定限速，根据 GVW 对重型车辆不仅实施基于车辆分类的限速，还实施基于 GVW 的限速。
