山区高速公路隧道路段与开放路段的事故影响因素分析

高速公路隧道构造特殊且通行环境复杂，因而通常事故多发。为探究高速公路隧道路段与开放路段事故影响因素和严重程度致因机理的差异，采集沪昆高速邵怀段2011—2016年期间1 537起事故为研究样本；以事故发生路段为响应变量构建逻辑回归模型，解释各种风险因素对事故发生路段倾向性的影响差异；分别针对隧道路段与开放路段建立模型研究事故伤害严重程度的影响因素。建立二元Logit回归模型分析事故的发生倾向性和2类路段的事故严重程度的影响因素；采用随机参数Logit模型以反映异质性条件对参数的影响。统计表明：与疲劳驾驶、未保持安全距离相关的事故发生在隧道路段的概率更高，其事故发生概率分别是开放路段的2.373和2.482倍；与隧道路段事故严重程度正相关的因素包括下坡（坡度2%以上）、夏季和超速行驶，其中下坡（坡度2%以上）段的严重事故发生的概率为上坡（坡度2%以上）的3.397倍，夏季的严重事故发生概率为秋季的3.951倍，超速行驶相关的严重事故发生概率为其他不当驾驶行为的4.242倍；与开放路段事故严重程度正相关的因素包括超速行驶和疲劳驾驶，其中超速行驶相关的严重事故概率是其他不当驾驶行为的2.713倍，疲劳驾驶相关的严重事故概率是其他不当驾驶行为的4.802倍。研究表明，山区高速公路隧道路段与开放路段的事故发生概率及其严重程度的影响因素存在一定的差异性，研究结论可为山区高速公路差异管理方案制定提供依据。

An Analysis of Influential Factors of Crashes at Tunnels and Open Sections of Mountainous Freeways

Freeway tunnels tend to have higher accident rates, due to their special engineering structure and complex traffic environments, compared to regular segments. In order to study the differences in mechanisms and factors influencing severity of crashes in tunnels and regular open sections on freeways, a total of 1 537 crashes taking place on Shaohuai Freeway from 2011 to 2016 are collected for the analysis. A binary Logit model considering the heterogeneity is used to explain the impacts of various risk factors on the likelihood of the locations of traffic crashes and to investigate the factors influencing severity of crashes taking place at tunnel and open sections. Statistical analysis results show that crashes associated with drowsy driving and unsafe following distance are more likely to occur in the tunnel sections, and the crash probability is 2.373 and 2.482 times higher than that in the open sections, respectively. In the tunnel sections, downhill (slope more than 2%), summer, and speeding are positively correlated to the likelihood of injury crashes, and the probability that crashes take place at downhill (slope more than 2%) sections is 3.397 higher than uphill (slope more than 2%) sections in resulting in serious accidents. It is also found that the probability of serious crashes taking place in the summer is 3.951 higher than that in the autumn; and the probability of the speeding behaviors is 4.242 higher than other inappropriate behavior. In the open sections, speeding and fatigue driving are likely to be associated with injury crashes, and the probability that speeding results in an injury crash is 2.713 higher than other inappropriate behavior. It is also found that the probability that the fatigue driving leading to an injury crash is 4.802 higher than other inappropriate behavior. The above results show that the factors influencing the crash propensity and severity at the two types of sections are different. The conclusions of this paper can be used to formulate road safety improvement plans over tunnel and open section segments of freeways.