Safety assessment of road sections and networks have historically relied on police-reported crash data. These data have several noteworthy and significant shortcomings, including under-reporting, subjectivism, post hoc assessment of crash causes and contributing factors, limited behavioural information, and omitted potential important crash-related factors resulting in an omitted variable bias. Moreover, crashes are relatively rare events and require long observation periods to justify expenditures. The rarity of crashes leads to a moral dilemma—we must wait for sufficient crashes to accrue at a site—some involving injuries and even death—to then justify improvements to prevent crashes. The more quickly the profession can end its reliance on crashes to assess road safety, the better.

Surrogate safety assessment methodologies, in contrast, are proactive in design, do not rely on crashes, and require shorter observation timeframes in which to formulate reliable safety assessments. Although surrogate safety assessment methodologies have been developed and assessed over the past 50 years, an overarching and unifying framework does not exist to date. A unifying framework will help to contextualize the role of various methodological developments and begin a productive discussion in the literature about how the various pieces do or should fit together to understand road user risk better.

This paper aims to fill this gap by thoroughly mapping traffic conflicts and surrogate safety methodologies. A total of 549 studies were meticulously reviewed to achieve this aim of developing a unifying framework. The resulting framework provides a consolidated and up-to-date summary of surrogate safety assessment methodologies and conflict measures and metrics.

Further work is needed to advance surrogate safety methodologies. Critical research needs to include identifying a comprehensive and reliable set of surrogate measures for risk assessment, establishing rigorous relationships between conflicts and crashes, developing ways to capture road user behaviours into surrogate-based safety assessment, and integrating crash severity measures into risk estimation.

历史上，对路段和网络的安全评估一直依靠警察报告的碰撞数据。这些数据有几个值得注意的重大缺陷，包括漏报，主观主义，事后对撞车原因和影响因素的事后评估，有限的行为信息以及潜在的与撞车有关的重要因素的遗漏，导致遗漏了可变偏差。此外，撞车是相对罕见的事件，需要较长的观察期才能证明支出合理。罕见的崩溃导致了道德上的两难境地：我们必须等待足够的崩溃在站点上发生，有些甚至涉及人身伤害甚至死亡，然后才有理由进行改进以防止崩溃。专业越快地结束对交通事故的评估，对道路安全的评估就越好。

相比之下，替代安全评估方法学在设计上是积极的，不依赖于碰撞，并且需要较短的观察时间框架来制定可靠的安全评估。尽管在过去的50年中已经开发和评估了替代安全评估方法，但是迄今为止，还没有一个总体统一的框架。一个统一的框架将有助于使各种方法学发展的作用与背景相关联，并在文献中开始进行富有成效的讨论，以讨论各个部分如何或应该如何配合以更好地理解道路使用者的风险。

本文旨在通过彻底映射交通冲突和替代安全方法来填补这一空白。认真审查了549项研究，以实现建立统一框架的目标。由此产生的框架提供了替代安全评估方法以及冲突措施和指标的最新汇总。

需要进一步的工作来推进替代安全方法。关键的研究需要包括确定一套全面而可靠的风险评估替代措施，在冲突和碰撞之间建立严格的关系，开发将道路使用者行为捕捉到基于替代的安全评估中的方法，以及将碰撞严重性措施纳入风险评估中。