高速公路遮挡物高度对停车视距的影响

Influence of Expressway Obstruction Height on Stopping Sight Distance

停车视距是保证行车安全的重要指标,多采用横净距公式法计算,但该法的使用条件均假定遮挡物高度对停车视距无影响,目前针对遮挡物高度对停车视距影响的定量研究报道极少。为了研究遮挡物高度对停车视距的影响,先在考虑遮挡物高度情况下对横净距公式进行了重新推导,后采用新公式分别研究了小客车和货车在不同遮挡物高度下,对曲线半径及横净距内移值的影响。结果发现,当遮挡物高度小于(视高+物高)/2时,采用新公式所计算的曲线半径较原横净距公式计算的曲线半径更小。据此,在工程设计中,应当考虑遮挡物高度对停车视距的影响,可减小工程规模,节约成本。

The stopping sight distance is an important indicator to ensure driving safety.Usually,the stopping sight distance is calculated using the lateral net distance formula,but the conditions for using this method assume that the height of obstacles has no effect on the stopping sight distance.Currently,there are very few quantitative research reports on the impact of obstacle height on the stopping sight distance.In order to study the influence of obstacle height on parking sight distance,the formula for lateral clear distance was first re derived considering the obstacle height.Then,the new formula was used to study the effects of different obstacle heights on the curve radius and lateral clear distance inward displacement of small buses and trucks.It was found that when the height of the obstruction is less than(visual height+object height)/2,the curve radius calculated using the new formula is smaller than that calculated using the original lateral clearance formula.Therefore,in engineering design,the influence of the height of obstacles on the parking sight distance should be considered,which can reduce the scale of the project and save investment.