公路客车横向加速度实验研究

摘要

To provide design basis for alignment parameters of different types of highways,the lateral accelerations,speeds,and trajectory curvature radii of passenger cars and buses on 12 highways having different design speed and topography were collected in field survey. The level of driving comfort on each test roads was estimated according to vehicle lateral acceleration. The characteristic percentile value of lateral acceleration on three road types,i. e. ,six-lane road,four-lane road and double-lane road,were presented. For passenger cars and buses on the three kinds of roads,regression models between lateral acceleration and trajectory radii,and between lateral acceleration and speed were established,including the average value model,the extremum value model,and the 85th percentile value model. The results show the following findings:(1 )driving comfort becomes poor as lane numbers decreases. For two-lane highways with a design speed of less than 30km/h,the uncomfortable travel on partial section is unbearable. (2 )The inflection point on cumulative probability curve of lateral acceleration appears at the 90-92th percentile,and the maximum value on two-lane highways exceeds 8 m/s2 . (3 ) The distribution of lateral acceleration tends to assemble as the trajectory curvature decreases or the lane number increases,and lateral acceleration distribution of buses is more centralized than the ones of passenger cars. (4 ) The extremum value model between lateral acceleration and trajectory radii and the 85 th percentile value model between lateral acceleration and speed can provide design control for the maximum/minimum value of road geometry elements,and the average value models can control the general value of road geometry elements.%为提供不同类型公路几何线形参数的计算依据，在12条不同地形环境、不同等级的公路上采集了小客车和大客车的横向加速度、行驶速度和轨迹曲率半径数据，评估了试验公路的行驶舒适性，给出了六车道、四车道、双车道3类公路的横向加速度特征分位值，针对不同公路类型和车型，建立了横向加速度-曲率半径和横向加速度-速度的均值模型、极限值模型和85分位值模型。研究结果表明：（1）车道数越少，行驶舒适性越差，设计速度低于30 km/h的双车道公路部分路段的行驶舒适性极差；（2）横向加速度累计频率曲线的拐点在第90～92分位，双车道公路的横向加速度最大值大于8 m/s2；（3）行驶轨迹越缓和、车道数越多，横向加速度分布越集中，且大客车的横向加速度分布要比小客车集中；（4）第85分位值模型可用于公路几何参数的最大值与最小值控制，均值模型可用于几何参数的一般值控制。