山区高速公路组合线形路段车道偏移行为

为在道路设计阶段确定平纵组合与相邻路段线形对车道偏离的影响，并为减少因道路线形因素引发的侧碰、追尾甚至车辆驶出路外事故提供改善依据，基于真实的山区高速公路道路设计参数及周边地形，搭建驾驶模拟场景，利用驾驶模拟试验获取小客车车道偏离数据，并对应获取车辆当前所在路段及上、下游路段的线形参数。以车辆车道内行驶为参照，沿道路行进方向，将车道偏离行为分为左偏驶离车道与右偏驶离车道。因车道偏离受驾驶人影响，采用双层Logit模型，分别判定道路线形及驾驶人层的影响。研究结果表明：相比直线路段，曲线更易引发车道偏离行为，驾驶人易偏向于曲线内侧行驶；上游300 m路段曲率差越大、平均车速越大，则车道偏离的概率增大；相对于缓坡（-2%≤坡度S≤2%），行驶于上坡（S>2%）或下坡（S<2%）路段时，车辆车道偏离概率减小；车辆行驶于外侧车道的左偏驶离车道概率大于行驶于内侧车道；驾驶人因素对左偏驶离车道的影响比例为8.8%，对右偏驶离车道的影响比例为25.6%。研究结论可从组合线形角度帮助工程师设计更安全的山区高速公路。

Effects of Combined Alignments of Mountainous Freeways on Lane Departure

The objective of this paper is to examine which geometric design characteristics, including combined alignments and adjacent segments, have significant influence on the probability of lane departure, which are not currently available and can help to reduce side-swipe, rear-end or single-vehicle run-off-road crashes through a better road design. The driving scene was reproduced in virtual reality by the exact road design parameters and roadside elements. With a driving simulator study, lane departure of passenger car data and the road alignments at the current segment, upstream and downstream adjacent segments were calculated. Along the driving direction, lane departures were classified into lane departure to the left and lane departure to the right with the reference category of lane keeping. Since lane departure events by driver are correlated, a two-level Logit model was employed to examine the contributory factors from drives and road alignments. The results indicate that lane departures are more likely happened on the curve compared with straight line. Drivers usually tend to keep to the inside of the curve. The difference between maximum and minimum horizontal curvatures and the average vehicle speed within the 300 m adjacent upstream alignment are found to be positively influenced lane departure. Drivers are more cautious on the downward slope (S<-2%) or upward slope (S>2%), which can reduce the probability of lane departure. Factors of driver-level random effects in the model results indicate that 8.8% of the total variation in the lane departure to the left in relation to lane keeping was accounted for by the drivers and 25.6% of the variation in the lane departure to the right was also accounted for by the drivers. These results can assist engineers in designing safer road alignments.