论文部分内容阅读
头灯视距（ ＨＬＳＤ） 已成为凹形竖曲线设计中的一个重要因素，因为夜间行车者需要足够的视距停车并依靠公路标线去保持匀速和正确的车道定位。鉴于独立的凹形竖曲线是基于停车视距的需要进行的二维设计，故目前的设计标准采用了最小凹曲线长度，然而很少有人研究三维公路线形中的ＨＬＳＤ。现在，ＨＬＳＤ 的三维分析研究人员开发的分析模式表明二维分析可能高估了与凹形竖曲线组合的平曲线上的ＨＬＳＤ。该文更精确地研究了路堤断面上的与平曲线组合的竖曲线，同时使用非对称复合竖曲线向您推荐一个更为经济的竖曲线设计方法。
Headlamp line-of-sight (HLSD) has become an important factor in the design of concave vertical curves because night-time drivers need adequate line-of-sight parking and depend on road markers to maintain uniform and correct lane positioning. Since the independent concave vertical curve is a two-dimensional design based on the need of parking line of sight, the current design standard adopts the minimum concave curve length. However, few people study the HLSD in the three-dimensional highway line. Analytical models developed by HLSD’s 3D analysis researchers now show that 2D analysis may overestimate HLSD on flat curves in combination with concave vertical curves. This paper investigates more accurately the vertical curve combined with the flat curve on the embankment section, and recommends a more economical vertical curve design method using the asymmetric composite vertical curve.