Lyles School of Civil Engineering, Purdue University, 3000 Kent Avenue, Suite C2-103, West Lafayette, IN 47907, United States.
Lyles School of Civil Engineering, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47907, United States.
Accid Anal Prev. 2021 Jan;149:105863. doi: 10.1016/j.aap.2020.105863. Epub 2020 Nov 11.
Although the frequency and severity of crashes are direct measures of road safety, crash data are typically of limited quality and they require long data collection periods to produce conclusive results. Surrogates of crashes that would allow a quick and accurate estimation of safety have been an active topic for years. Among multiple alternatives, traffic conflicts have been established as a promising surrogate measure. This paper is aimed to demonstrate the validity of failure-caused traffic conflicts by applying a recently proposed Lomax-based method to estimate the expected number of crashes from observed traffic conflicts. The data collected in the naturalistic driving program, the Second Strategic Highway Research Program (SHRP2), were used in the validation task. The rear-end crashes recorded during the SHRP2 program and the corresponding rear-end traffic conflicts were analyzed for three categories of drivers: young male, mature male, and mature female. Past research has indicated that these three categories have a distinctively different proneness to involvement in crashes. Out of all rear-end traffic conflicts included in the SHRP2 database, 1.4 % were used to estimate the crash frequencies and rates for each studied type of driver. The Lomax distribution was applied within the counterfactual framework. Then, the conflict-based crash rate estimates were compared to the crash rates of the studied types of drivers calculated from all the rear-end crashes observed in the SHRP2 study period. The conflict-based rate estimates followed well the crash-based rates and the existing knowledge about the safety performance of the studied drivers. The conflict-based results confirmed the over-representation of young male drivers in crashes. It was also confirmed that mature male drivers are involved in rear-end crashes more frequently than mature female drivers. The results demonstrate both the validity of the Lomax-based analysis of failure-caused traffic conflicts and the benefit of traffic conflicts analysis that considerably reduces a period of data collection from years for crashes to days or weeks for traffic conflicts.
尽管事故频率和严重程度是衡量道路安全的直接指标，但事故数据的质量通常有限，并且需要长时间的数据收集才能得出结论。多年来，人们一直致力于寻找能够快速准确地评估安全性的事故替代指标。在多种替代方案中，交通冲突已被确立为一种很有前途的替代指标。本文旨在通过应用最近提出的基于 Lomax 的方法从观察到的交通冲突中估计预期的事故数量，证明导致事故的交通冲突的有效性。验证任务使用了自然驾驶计划（Second Strategic Highway Research Program，SHRP2）中收集的数据。对 SHRP2 计划中记录的追尾事故和相应的追尾交通冲突进行了分析，共涉及三类驾驶员：年轻男性、成熟男性和成熟女性。过去的研究表明，这三类驾驶员在发生事故的倾向性方面存在明显差异。在 SHRP2 数据库中包含的所有追尾交通冲突中，有 1.4%被用于估计每个研究类型驾驶员的事故频率和速率。Lomax 分布应用于反事实框架内。然后，将基于冲突的事故率估计值与从 SHRP2 研究期间观察到的所有追尾事故中计算出的研究类型驾驶员的事故率进行比较。基于冲突的事故率估计值与基于事故的事故率吻合良好，并且与研究驾驶员的安全性能的现有知识相符。基于冲突的结果证实了年轻男性驾驶员在事故中所占比例过高。还证实了成熟男性驾驶员比成熟女性驾驶员更频繁地发生追尾事故。研究结果证明了基于 Lomax 的导致事故的交通冲突分析的有效性，以及交通冲突分析的益处，即可以将数据收集的时间从几年减少到几天或几周。
