高速公路中央分隔带停车视距评价方法研究

Study on Method of Evaluating Stopping Sight Distance of Median Strip in Expressway

通过对多条高速公路的小客车视距进行检查,发现中分带视距存在很多问题,为了解决在具有中分带的道路上,尤其是靠近中央分隔带护栏的左转曲线路段的停车视距不足的问题;通过阅读大量文献,对影响停车视距模型的各因素和现有停车视距模型存在的问题进行了分析;以车辆在曲线路段运行的行车动力学模型为基础,从影响停车视距模型本身的参数入手,在运行速度、道路纵坡、纵向摩阻系数3个方面对停车视距模型进行修正,并从目标物高度的角度出发,对停车视距不满足要求的路段提出建议,并进行了实例验证。研究结果表明:通过提高目标物高度至0.8 m,可以很好地解决曲线路段的停车视距问题,避免中分带护栏特殊设计或者增加高速公路不必要的占地、影响速度的一致性。

Through inspection of the stopping sight distance of cars in many expressways, it has been found that there are many problems in the stopping sight distance of median strip. In order to solve the problem of the insufficient stopping sight distance on the roads with median strip, especially on the left-turn curve sections near the fences of median strip, through reading a large amount of literatures, the factors affecting the stopping sight distance model and the existing problems in the current stopping sight distance models are analyzed. Based on the dynamic model of the vehicle running on curve section, starting from the parameters affecting the stopping sight distance model itself, the stopping sight distance model is modified in terms of driving speed, road longitudinal slope, and longitudinal friction coefficient. From the perspective of object height, some suggestions for the sections that do not meet the requirements for stopping sight distance are proposed, and an example verification is conducted. The result shows that by increasing the object height to 0. 8 m, the problem of stopping sight distance of curve sections can be well solved to avoid special design with guardrails or to increase unnecessary land occupation on expressways which affecting the consistency of driving speed.