Department of Civil and Environmental Engineering, The Pennsylvania State University, 406 B Sackett Building, University Park, PA 16802, United States.
Kittelson & Associates, Incfc 409 N 2nd Street, Suite 201, Harrisburg, PA 17101, United States.
Accid Anal Prev. 2024 Jan;194:107371. doi: 10.1016/j.aap.2023.107371. Epub 2023 Nov 8.
Horizontal curves are known to be more crash-prone than tangent sections particularly with respect to roadway departure crashes. Rumble strips are an effective countermeasure to mitigate various types of roadway departure crashes. While existing studies on the safety effectiveness of rumble strips have primarily used before-after study designs or cross-sectional methods for crash modification factor (CMF) estimation, these methods often suffer from imbalanced datasets and larger standard errors, especially when the sample size is small. To address this, this study applies the propensity score potential outcome (PSPO) framework to estimate CMFs for centerline rumble strips, shoulder rumble strips, and their combined application on horizontal curves. In addition to contributing to the development of CMFs by crash severity, this study also examines the effects of rumble strips on collision types, highlighting their impact on vehicle maneuvering and collision characteristics. The analysis is conducted on horizontal curves on two-lane rural roads in Pennsylvania, utilizing crash data from 2017 to 2021. The PSPO method effectively reduces bias between sites with and without rumble strips, and the resulting statistical models align with engineering judgment. The findings indicate that centerline rumble strips reduce opposite direction sideswipe and head-on crashes but increase run off the road and hit fixed object crashes. Shoulder rumble strips, either alone or in combination with centerline rumble strips, decrease crash frequencies for most types except opposite direction sideswipe and head-on crashes. However, shoulder rumble strips alone are more effective at reducing crash frequencies on horizontal curves than when combined with centerline rumble strips.
弯道比直线段更容易发生碰撞事故，尤其是在车辆偏离车道的情况下。颠簸带是一种减少各种类型车道偏离碰撞的有效措施。虽然现有关于颠簸带的安全效果的研究主要使用前后研究设计或横截面方法来估计碰撞修正系数（CMF），但这些方法往往受到不平衡数据集和较大标准误差的影响，尤其是在样本量较小时。为了解决这个问题，本研究应用倾向评分潜在结果（PSPO）框架来估计中心线颠簸带、路肩颠簸带及其在弯道上的组合应用的 CMF。除了通过碰撞严重程度为 CMF 的发展做出贡献外，本研究还研究了颠簸带对碰撞类型的影响，强调了它们对车辆操纵和碰撞特征的影响。该分析在宾夕法尼亚州的两条车道农村道路的弯道上进行，使用了 2017 年至 2021 年的碰撞数据。PSPO 方法有效地减少了有和没有颠簸带的地点之间的偏差，并且得出的统计模型符合工程判断。研究结果表明，中心线颠簸带减少了对向侧面碰撞和正面碰撞，但增加了驶出路外和撞向固定物体的碰撞。路肩颠簸带，无论是单独使用还是与中心线颠簸带一起使用，除了对向侧面碰撞和正面碰撞外，都降低了大多数类型的碰撞频率。然而，路肩颠簸带单独使用在减少弯道上的碰撞频率方面比与中心线颠簸带一起使用更有效。
