Introduction: This study investigates the impact of several risk factors (i.e., roadway, driver, vehicle, environmental, and barrier-specific characteristics) on the injury severity resulting from barrier-related crashes and also on barrier-hit outcomes (i.e., vehicle containment, vehicle redirection, and barrier penetration). A total of 1,685 barrier-related crashes, which occurred on three major interstate highways (I-65, I-85, and I-20) in the state of Alabama, were collected for a seven-year period (2010–2016), and all relevant information from the police reports was reviewed. Features that were rarely explored before (e.g., median width, barrier length, barrier offset or lateral position, left shoulder width, blockout type, and number of cables) were also collected and examined. Two types of longitudinal barriers were analyzed: high-tension cable barriers installed on medians and strong-post guardrails installed on medians and/or roadsides. Method: Two separate mixed logit (MXL) models were used to analyze crash injury severity in median and roadside barrier-related crashes. Two additional MXL models were separately adopted for median and roadside barrier-related crashes to estimate the probability of three barrier-hit outcomes (vehicle containment, vehicle redirection, and barrier penetration). Results: The results of crash injury severity MXL models showed that, for both median and roadside barrier crashes, barrier penetration, female drivers, and driver fatigue were associated with a higher probability of injury or fatal crashes. The results of barrier-hit MXL models showed that longer barrier length, Brifen cable barrier system, and barrier lateral position were significant predictors of median barrier-hit outcomes, whereas dark lighting condition, driving under the influence (DUI), presence of curved freeway sections, and right shoulder width significantly contributed to roadside barrier-hit outcomes. Conclusions: The MXL model succeeded in identifying several contributing factors of crash severity and barrier-hit outcomes along Alabama’s interstate highways. Practical applications: One study application is to design longer barrier run length (greater than 1230 feet or 0.2 miles) to reduce the barrier penetration likelihood.

介绍：本研究调查了几个风险因素（即道路、驾驶员、车辆、环境和特定于障碍物的特征）对障碍物相关碰撞造成的伤害严重程度以及对障碍物撞击结果（即车辆遏制、车辆重定向和屏障穿透）。在阿拉巴马州的三条主要州际公路（I-65、I-85 和 I-20）上共收集了 1,685 起与障碍相关的碰撞事故，这些事故发生在七年期间（2010-2016 年），并审查了警方报告中的所有相关信息。以前很少探索的特征（例如，中间宽度、屏障长度、屏障偏移或横向位置、左肩宽度、阻塞类型和电缆数量）也被收集和检查。分析了两种类型的纵向障碍：方法：使用两个独立的混合 logit (MXL) 模型来分析与中间和路边障碍相关的碰撞中的碰撞伤害严重程度。两个额外的 MXL 模型分别用于与中间和路边障碍相关的碰撞，以估计三种撞到障碍结果的概率（车辆遏制、车辆重定向和障碍穿透）。结果：碰撞伤害严重程度 MXL 模型的结果表明，对于中间和路边障碍物碰撞，障碍物穿透、女性驾驶员和驾驶员疲劳与更高的受伤或致命碰撞概率相关。障碍物撞击 MXL 模型的结果表明，更长的障碍物长度、Brifen 缆索障碍物系统和障碍物横向位置是中值障碍物撞击结果的重要预测因素，而黑暗照明条件、影响驾驶 (DUI)、弯曲高速公路的存在路段和右肩宽对路边障碍物撞击结果有显着影响。结论： MXL 模型成功地确定了阿拉巴马州州际公路沿线的碰撞严重程度和障碍物撞击结果的几个影响因素。实际应用： 一项研究应用是设计更长的屏障运行长度（大于 1230 英尺或 0.2 英里）以减少屏障穿透的可能性。