公路货运通道路侧事故多发路段判别与线形设计

Identification of roadside accident blackspot and geometric design of dedicated freight corridor on highways

为了优化公路货运通道线形设计,降低货车事故概率,将车速、圆曲线半径、纵坡坡度、超高横坡度、硬路肩宽度、圆曲线加宽、路面附着系数、车型(载重货车、铰接列车)作为风险因素,利用PC-Crash软件开展事故模拟试验;通过二元Logistic回归分析筛选显著性风险因素,构建货运通道路侧事故概率预测模型;根据概率模型预测结果,借助“累计频率曲线法”思想,给出路侧事故潜在多发点和路侧事故多发点概率阈值,提出了货运通道路侧事故多发路段判别方法;针对路侧事故多发路段,利用分类树CART(classification and regression tree)算法,开展货运通道线形优化设计研究。结果表明:显著性风险因素对路侧事故影响的重要度由大到小依次为车速、圆曲线半径、路面附着系数、车型、硬路肩宽度、纵坡坡度和超高横坡度;对于圆曲线半径R≤400 m、运行速度60 km/h<v≤80 km/h的货运通道路段,设计纵坡坡度应<4%,若无法满足纵坡设计要求,设计超高横坡度应≥4%;对于运行速度80 km/h<v≤100 km/h,圆曲线半径400 m<R≤800 m的货运通道路段,应设置硬路肩宽度≥2.25 m;此外,增加硬路肩宽度对于减少载重货车路侧事故风险较为显著。

To optimize the geometric design of dedicated freight corridors on highways and reduce the probability of truck accidents,PC-Crash software was used to conduct accident simulation tests with speed,horizontal curve radius,longitudinal slope,superelevation slope,hard shoulder width,widen value of curve,adhesion coefficient,and vehicle type(heavy trucks and articulated trains)as risk factors.The significant risk factors were screened by binary Logistic regression analysis,and the prediction model of roadside accident probability on dedicated freight corridors was constructed.Based on the probabilistic prediction results and the thought of"cumulative frequency curve method",the probability thresholds of potential blackspot and frequent blackspot of roadside accidents were given,and the identification method of roadside accident blackspot on dedicated freight corridors was proposed.In view of the sections with frequent occurrence of roadside accidents on dedicated freight corridors,the optimization geometric design of dedicated freight corridors was carried out by using classification and regression tree(CART)algorithm.Results show that the importance of significant risk factors on roadside accidents from the largest to the smallest was as followings:speed,horizontal curve radius,adhesion coefficient,vehicle type,hard shoulder width,longitudinal slope,and superelevation slope.For the dedicated freight corridor section with horizontal curve radius of R≤400 m and operating speed of 60 km/h<v≤80 km/h,the longitudinal slope should be<4%;if this design requirements were not met,the superelevation slope should be≥4%.For the section of dedicated freight corridor with operating speed of 80 km/h<v≤100 km/h and horizontal curve radius of 400 m<R≤800 m,the hard shoulder width should be≥2.25 m.Additionally,increasing the hard shoulder width had a significant effect on reducing the risk of roadside accidents for heavy trucks.