Influence of Expressway Obstruction Height on Stopping Sight Distance
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.
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