对于司机而言，路面看起来可能很寻常，但当雨开始下时，它对轮胎的抓地力就会发生变化。在急转弯处，抓地力的丧失会增加车辆冲出道路的风险。美国联邦公路管理局（FHWA）在2020年开展的一项研究调查了交通部门采用高摩擦表面处理（HFST）解决该问题时的效果。
A road surface can look ordinary to drivers, but its grip on tires can change when rain begins. On sharp curves, that loss of grip can increase the risk of a roadway-departure crash. A 2020 Federal Highway Administration (FHWA) study examined what happened when transportation agencies addressed that problem with high-friction surface treatment (HFST).Researchers analyzed 157 treated curves across West Virginia, Pennsylvania, and Kentucky and found that wet-road crashes fell by an estimated 83%, while total crashes declined by 57%.
研究人员分析了西弗吉尼亚州、宾夕法尼亚州和肯塔基州的157处经处理的弯道，发现雨天道路交通事故估计下降了83%，而总事故下降了57%。这些降幅具有统计学意义。这些发现在湿滑路面、车速和道路几何形状增加了对摩擦力需求的弯道上，进一步强化了将高摩擦表面处理作为一种有针对性安全措施的理由。为什么弯道在雨中会变得危险行驶在弯道上的车辆依靠路面提供足够的摩擦力来保持轮胎的行驶轨迹。
The reductions were statistically significant. The findings strengthen the case for HFST as a targeted safety measure at curves where wet pavement, speed and road geometry raise friction demands. Why curves can become dangerous in the rainA vehicle negotiating a curve relies on the pavement to provide enough friction for its tires to maintain their path.
当路面变湿时，可用的摩擦力可能会下降，从而使司机的容错空间变小。高摩擦表面处理正是专为此类地点设计的。根据美国联邦公路管理局的说法，该处理使用通过聚合物树脂粘合剂粘合到路面上的高质量骨料。通常使用煅烧铝矾土，因为它能提供高且持久的摩擦力。高摩擦表面处理通常不用于整个公路走廊，而是用于摩擦相关事故集中的特定地点，如弯道、匝道和交叉路口。
When the surface becomes wet, available friction can fall, leaving drivers with less margin for error. HFST is designed specifically for such locations. According to FHWA, the treatment uses high-quality aggregate bonded to the pavement with a polymer resin binder. Calcined bauxite is commonly used because it provides high and durable friction. Rather than being intended for entire highway corridors, HFST is generally used at specific locations such as curves, ramps, and intersections where friction-related crashes are concentrated.
2020年美国联邦公路管理局的研究尤为重要，因为它采用了经验贝叶斯事前事后方法论，这是一种旨在解释回归均值和交通状况变化等因素的统计方法。在这三个州中，经处理地点的平均年交通量约为每天6000至8000辆车，具体取决于各州。雨天道路交通事故改善最为明显最显著的结果出现在高摩擦表面处理旨在预防的事故类型上。
The 2020 FHWA study was especially significant because it used an empirical Bayes before-and-after methodology, a statistical approach intended to account for factors such as regression to the mean and changes in traffic conditions. Across the three states, the treated sites had an average annual traffic volume of roughly 6,000 to 8,000 vehicles, depending on the state. Wet-road crashes showed the biggest improvementThe strongest result was in the type of crash HFST is designed to prevent.
美国联邦公路管理局报告称，综合弯道地点的雨天道路交通事故减少了83%。冲出道路事故下降了72%，人员受伤事故下降了48%，涉及与相向行驶车辆发生正面相撞或侧面擦撞的事故下降了31%。总事故下降了57%。潜在的数据显示了研究人员为何认为这些发现具有重要意义。在这三个州中，分析记录了处理后的329起事故，而如果没有高摩擦表面处理，经验贝叶斯估计会发生约768起事故。在雨天道路交通事故方面，处理后发生了82起，而估计没有处理的话会发生496起。
FHWA reported an 83% reduction in wet-road crashes at the combined curve sites. Roadway-departure crashes declined by 72%, injury crashes by 48%, and crashes involving head-on or sideswipe collisions with vehicles traveling in the opposite direction by 31%. Total crashes fell by 57%. The underlying numbers show why the researchers considered the findings significant. Across the three states, the analysis recorded 329 crashes after treatment, compared with an empirical-Bayes estimate of about 768 crashes that would have been expected without HFST. For wet-road crashes, 82 occurred after treatment against an estimated 496 expected without it.
雨天道路交通事故的事故修正系数为0.168，这意味着处理后的事故率约为未处理时预期水平的16.8%。这相当于减少了约83%。发表在《交通研究记录》上的一篇研究论文得出了类似的结论，发现高摩擦表面处理在弯道上具有巨大且具有统计学意义的安全效益，特别是对于雨天道路和冲出道路事故。研究人员还发现，该处理的有效性与摩擦力的改善程度、交通量以及处理前预期的事故数量有关。
The crash modification factor for wet-road crashes was 0.168, meaning the post-treatment crash rate was about 16.8% of the expected level without treatment. That corresponds to an approximately 83% reduction . A research paper published in Transportation Research Record reached a similar conclusion, finding substantial and statistically significant safety benefits for HFST at curves, particularly for wet-road and roadway-departure crashes. The researchers also found that the treatment's effectiveness was related to the amount of friction improvement, traffic volume, and the number of crashes expected before treatment.
从路面升级到安全策略此外，研究人员还调查了高摩擦表面处理在安装后是否能保持其摩擦性能。在同时进行的另一项美国联邦公路管理局研究中，研究人员在佐治亚州和宾夕法尼亚州的99个地点测量了高摩擦表面处理施工前后的摩擦力。研究发现，高摩擦表面处理显著改善了摩擦力，并甚至在长期的重型交通下仍能保持高摩擦水平。这种维持高摩擦值的能力至关重要，因为高摩擦表面处理仅应用于特定地点。
From a pavement upgrade to a safety strategyIn addition, researchers looked at whether HFST could preserve its friction performance after installation. In another FHWA study conducted concurrently, friction was measured both prior to and following the application of the HFST at 99 sites in Georgia and Pennsylvania. The study found that HFST significantly improved friction and maintained high friction levels even under heavy traffic over time. This ability to sustain high friction values is crucial since HFST is applied only in specific locations.
更近期的研究也对该处理进行了考察。《事故分析与预防》2024年的一项研究结合使用倾向得分匹配与经验贝叶斯事前事后方法，分析了宾夕法尼亚州水平弯道上的高摩擦表面处理。研究发现，在所考察的事故类型和严重程度中，降幅具有统计学意义，这为早期的美国联邦公路管理局的研究结果提供了进一步的证据。
More recent research has also examined the treatment. A 2024 study in Accident Analysis & Prevention analyzed HFST on horizontal curves in Pennsylvania using propensity-score matching combined with an empirical Bayes before-and-after approach. It found statistically significant reductions across the crash types and severities examined, adding further evidence to the earlier FHWA findings.
尽管如此，83%这一数字不应被视为对每个经处理的弯道都会看到相同降幅的保证。事故率取决于几个因素，包括交通水平、天气、司机行为和道路类型。然而，美国联邦公路管理局的研究本身表明，安全收益的水平是因地点而异的。公路部门无需重建每个危险地点，而是可以在轮胎抓地力最关键的地方使用高摩擦表面处理。
Still, the 83% figure should not be treated as a guarantee that every treated curve will see the same reduction. Crash rates depend on several factors, including traffic levels, weather, driver behavior, and roadway type. However, the FHWA research itself showed that the level of safety gain was site-specific. Rather than rebuilding every dangerous site, highway authorities can use HFST where extra tire grip is most critical.