Department of Civil Engineering, South Tehran Branch, Azad University, Tehran 1584715414, Iran.
Faculty of Civil Engineering, Shahrood University of Technology, Shahrood 3619995161, Iran.
Int J Environ Res Public Health. 2020 Aug 17;17(16):5975. doi: 10.3390/ijerph17165975.
Road transportation poses one of the significant public health risks. Several contributors and factors strongly link public health and road safety. The design and advancement of higher-quality roads can significantly contribute to safer roads and save lives. In this article, the safety aspect of the roads' horizontal curves under the standard of the American Association of State Highway Transportation Officials (AASHTO) is evaluated. Several factors, including vehicle weight, vehicle dimensions, longitudinal grades, and vehicle speed in the geometric design of the horizontal curves, are investigated through a multi-body dynamic simulation process. According to the AASHTO, a combination of simple circular and clothoid transition curves with various longitudinal upgrades and downgrades was designed. Three vehicles were used in this simulation, including a sedan, a bus, and a 3-axle truck. The analysis was based on the lateral friction between the tire and the pavement and also the safety margin parameter. The results showed that designers must differentiate between light and heavy vehicles, especially in curves with a high radius. Evaluation of longitudinal grade impacts indicated that the safety margin decreases when the vehicle is entering the curve. Safety margin reduction on the clothoid curve takes place with a lower grade toward the simple circular curve. By increasing the speed, the difference between lateral friction demand obtained from simulation and lateral friction demand proposed by AASHTO grows. The proposed novel methodology can be used for evaluating road safety.
道路交通构成了重大公共卫生风险之一。有几个因素和贡献者将公共卫生和道路安全紧密联系在一起。更高质量道路的设计和改进可以显著促进道路安全并拯救生命。本文评估了美国州公路和运输官员协会（AASHTO）标准下道路水平曲线的安全方面。通过多体动力学模拟过程，研究了车辆重量、车辆尺寸、纵向坡度和车辆速度等几个因素在水平曲线的几何设计中的作用。根据 AASHTO 的规定，设计了结合简单圆形和回旋线过渡曲线的组合，以及各种纵向升级和降级。该模拟使用了三种车辆，包括轿车、公共汽车和三轴卡车。分析基于轮胎与路面之间的横向摩擦力和安全裕度参数。结果表明，设计者必须区分轻载和重载车辆，特别是在半径较大的曲线上。对纵向坡度影响的评估表明，车辆进入曲线时安全裕度会降低。在向简单圆形曲线过渡的过程中，布氏曲线的安全裕度减小。随着速度的增加，模拟得出的横向摩擦力需求与 AASHTO 提出的横向摩擦力需求之间的差异增大。所提出的新方法可用于评估道路安全。
