山区高速公路平纵组合路段设计安全评估

Safety Evaluation of Combined Horizontal and Vertical Alignments on Mountainous Freeways

为定量评估山区高速公路平纵组合路段的设计安全水平,建立了基于驾驶模拟技术的安全评价方法.基于湖南省永吉高速公路的道路设计参数,在驾驶模拟器中搭建高速公路驾驶场景,以平曲线上坡段、平曲线下坡段、平曲线凸曲线段和平曲线凹曲线段4类平纵组合路段为研究对象,选取评价指标,运用多元线性回归建立以驾驶模拟数据为基础的道路安全评价模型.模型结果表明:4类平纵组合路段上,平曲线曲率均与横向加速度呈正相关;平曲线上坡段,最大纵坡坡度与横向加速度呈负相关,而圆曲线长度与横向加速度呈正相关;平曲线下坡段,最大纵坡坡度与横向加速度呈负相关.此外,根据横向加速度分布特征,将平纵组合路段安全性划分为"GOOD"、"FAIR"和"POOR"三个等级.

A safety evaluation method was established based on the driving simulator for evaluating combined horizontal and vertical alignments on mountainous freeways quantitatively. Based on the exact road design parameters from the design blueprint of Yongji freeway in Hunan Province,the driving scene was set up in Tongji University’s eight-degree-of-freedom driving simulator. The research objects were upslope ＋ horizontal curve combined alignment,downslope ＋ horizontal curve combined alignment,crest vertical curve ＋ horizontal curve combined alignment and sag vertical curve ＋ horizontal curve combined alignment. With selected evaluation index,multiple linear regression was adopted to develop safety evaluation models based on the driving simulation data. Results indicate that the lateral acceleration is positively correlated with the reciprocal of the radius in the model of all combined alignments. In the model of upslope ＋ horizontal curve combined alignment,lateral acceleration is negatively correlated with maximum grade,and the lateral acceleration is positively correlated with curve length. In the model ofdownslope ＋ horizontal curve combined alignment,the lateral acceleration is negatively correlated with maximum grade. The 50 th/85 th percentile values of lateral accelerations were found as the safety thresholds of ＂GOOD＂,＂FAIR＂and ＂POOR＂according to the distribution of them.