Johnson Nicholas S, Gabler Hampton C
a Virginia Tech , Blacksburg , Virginia.
Traffic Inj Prev. 2015;16 Suppl 2:S103-8. doi: 10.1080/15389588.2015.1065976.
The goal of this study is to evaluate the crash performance of guardrail end terminals in real-world crashes. Guardrail end terminals are installed at the ends of guardrail systems to prevent the rail from spearing through the car in an end-on collision. Recently, there has been a great deal of controversy as to the safety of certain widely used end terminal designs, partly because there is surprisingly little real-world crash data for end terminals. Most existing studies of end terminal crashes used data from prior to the mid-1990s. Since then, there have been large improvements to vehicle crashworthiness and seat belt usage rates, as well as new roadside safety hardware compliant with National Cooperative Highway Research Program (NCHRP) Report 350, "Recommended Procedures for the Safety Performance Evaluation of Highway Features." Additionally, most existing studies of injury in end terminal crashes do not account for factors such as the occurrence of rollover. This analysis uses more recent crash data that represent post-1990s vehicle fleet changes and account for a number of factors that may affect driver injury outcome and rollover occurrence.
Passenger vehicle crashes coded as involving guardrail end terminals were identified in the set of police-reported crashes in Michigan in 2011 and 2012. End terminal performance was expected to be a function of end terminal system design. State crash databases generally do not identify specific end terminal systems. In this study, the coded crash location was used to obtain photographs of the crash site prior to the crash from Google Street View. These site photographs were manually inspected to identify the particular end terminal system involved in the crash. Multiple logistic regression was used to test for significant differences in the odds of driver injury and rollover between different terminal types while accounting for other factors.
A total of 1,001 end terminal crashes from the 2011-2012 Michigan State crash data were manually inspected to identify the terminal that had been struck. Four hundred fifty-one crashes were found to be suitable for analysis. Serious to fatal driver injury occurred in 3.8% of end terminal crashes, moderate to fatal driver injury occurred in 11.8%, and 72.3% involved property damage only. No significant difference in moderate to fatal driver injury odds was observed between NCHRP 350 compliant end terminals and noncompliant terminals. Car drivers showed odds of moderate to fatal injury 3.6 times greater than LTV drivers in end terminal crashes. Rollover occurrence was not significantly associated with end terminal type.
Car drivers have greater potential for injury in end terminal crashes than light truck/van/sport utility vehicle drivers. End terminal designs compliant with NCHRP 350 did not appear to carry different odds of moderate driver injury than noncompliant end terminals. The findings account for driver seat belt use, rollover occurrence, terminal orientation (leading/trailing), control loss, and the number of impact events. Rollover and nonuse of seat belts carried much larger increases in injury potential than end terminal type. Rollover did not appear to be associated with NCHRP 350 compliance.
本研究的目的是评估护栏终端在实际碰撞事故中的防撞性能。护栏终端安装在护栏系统的末端，以防止在正面碰撞时护栏刺穿车辆。最近，对于某些广泛使用的终端设计的安全性存在大量争议，部分原因是终端的实际碰撞数据出奇地少。大多数现有的终端碰撞研究使用的是20世纪90年代中期以前的数据。从那时起，车辆的防撞性能和安全带使用率有了很大提高，并且出现了符合美国国家公路合作研究计划（NCHRP）第350号报告《公路设施安全性能评估推荐程序》的新型路边安全硬件。此外，大多数现有的终端碰撞伤害研究没有考虑诸如翻车事故发生等因素。本分析使用了更新的碰撞数据，这些数据反映了20世纪90年代后的车辆车队变化，并考虑了一些可能影响驾驶员伤害结果和翻车事故发生的因素。
在2011年和2012年密歇根州警方报告的碰撞事故中，识别出编码为涉及护栏终端的乘用车碰撞事故。终端性能预计是终端系统设计的函数。州碰撞数据库通常不会识别特定的终端系统。在本研究中，使用编码的碰撞位置从谷歌街景获取碰撞前碰撞现场的照片。对这些现场照片进行人工检查，以识别碰撞中涉及的特定终端系统。使用多元逻辑回归来测试不同终端类型之间驾驶员受伤和翻车几率的显著差异，同时考虑其他因素。
对2011 - 2012年密歇根州碰撞数据中的1001起终端碰撞事故进行了人工检查，以识别被撞击的终端。发现451起碰撞事故适合进行分析。在终端碰撞事故中，3.8%的事故导致驾驶员受重伤至致命伤，11.8%的事故导致驾驶员受中度至致命伤，72.3%的事故仅涉及财产损失。符合NCHRP 350标准的终端与不符合标准的终端在驾驶员中度至致命伤几率上没有显著差异。在终端碰撞事故中，汽车驾驶员受中度至致命伤的几率是轻型卡车/面包车/运动型多用途车驾驶员的3.6倍。翻车事故的发生与终端类型没有显著关联。
在终端碰撞事故中，汽车驾驶员比轻型卡车/面包车/运动型多用途车驾驶员更容易受伤。符合NCHRP 350标准的终端设计在驾驶员中度受伤几率方面似乎与不符合标准的终端没有差异。研究结果考虑了驾驶员安全带使用情况、翻车事故发生情况、终端方向（前导/尾随）、失控情况以及碰撞事件数量。翻车和不使用安全带导致的受伤可能性增加幅度远大于终端类型。翻车似乎与符合NCHRP 350标准无关。
