山区高速公路超车道小客车停车视距安全性

Safety of stop sight distance of freeway passing lane for passenger car in mountainous area

行车视距是道路设计一个重要的控制指标。山区高速公路行车时,超车道上左转弯因车速高和距离中央分隔带近,驾驶人视距常受限,对行车安全造成较大影响。针对现有二维停车视距模型参数选择不够合理问题,采用运行速度预测和实际速度测试相结合,以运行速度和制动减速度综合修正小客车二维停车视距模型,根据不同纵坡值计算超车道小客车停车视距。在山区高速公路横净距一般设计值为2.45m和2m条件下,计算得出满足超车道左转弯停车视距的最小圆曲线半径。最后建立了考虑横断面和超车道左侧影响因素的三维动态视距模型。研究结果表明:现有山区高速公路超车道小客车停车视距设计值偏小,对于设计速度为100km/h和80km/h,超车道小客车停车视距相应推荐为200m和170m;建议在左转弯视距不足处加宽横净距和增设视线诱导安全设施,以保证实际超车道小客车行车安全。

Stop sight distance（SSD）is an important control parameter in highway design.The freeway sight distance is always blocked because the passenger car turns left with high speed and is very close to the medians in mountainous area,which has great impact on safety.Since the parameters of SSD model are adopted unreasonably,the combination operating speeds prediction and the field test was taken into consideration,and operating speed and braking deceleration were synthesized to modify the SSD model of passenger car.The SSD values were calculated based on different longitudinal gradients.Adopting design value of horizontal sightline offset of 2.45 mor 2m,the minimum left curve radii were calculated to satisfy the need of SSD.Highway 3Ddynamic sight distance model was established with consideration of influencing factors of cross section and passing lane.The results show that the design values of horizontal sightline offset are always not long enough,and SSD are 200 mand 170mfor the design speeds of100km/h and 80km/h.In addition,the horizontal sightline offset should be improved and sight guidingsafety facilities should be added when left turn sight distance is not long enough to ensure the actual driving safety in freeway passing lane in mountainous area.7tabs,3figs,16 refs.