Research has revealed the safety benefits of shoulder improvements on highways are significant. The study aimed to assess the impact of paved shoulder width on the frequency of fatal crashes in case of heterogeneous traffic on a rural four-lane divided highway in India. A matched case-control design was employed to evaluate the safety effectiveness of the paved shoulder width on fatal crashes. The impact of shoulder widths on victims of motorized two-wheelers (MTW) users, slow-moving vehicles and rear-end fatal crashes were also analyzed. The study stretch was divided into segments of 100 m. Each segment was linked to the traffic volume, speed, geometric characteristics, and roadside hazards characteristics. Analysis of the crash data revealed that 39% of the total crashes are due to rear-end collisions, mostly occurring at nighttime. The model results are interpreted concerning segments with no shoulder as the baseline category. Model results suggest that paved shoulder has safety benefits for all road users up to 1.5 m shoulder width. The provision of paved shoulders reduced the risk of all fatal crashes and improved the safety of pedestrians and slow-moving vehicles. However, the safety of MTW users reduced on segments having paved shoulder width more than 2 m. Also, segments with a paved shoulder width of more than 1.5 m have a higher risk of rear-end fatal crashes than no shoulder segments. This study findings have a direct bearing on the geometric standards recommended by the road authorities in India.

研究表明，公路路肩改善的安全效益非常显着。该研究旨在评估铺砌肩宽对印度农村四车道分隔公路上异质交通情况下致命撞车频率的影响。采用匹配的病例对照设计来评估铺砌肩宽在致命事故中的安全有效性。还分析了肩宽对机动两轮车 (MTW)​​ 用户、缓慢行驶的车辆和追尾致命事故的受害者的影响。研究路段被分成 100 m 的段。每个部分都与交通量、速度、几何特征和路边危险特征相关联。对碰撞数据的分析表明，39% 的碰撞事故是由于追尾事故造成的，而且大多发生在夜间。模型结果被解释为没有肩部的段作为基线类别。模型结果表明，铺砌路肩对肩宽达 1.5 m 的所有道路使用者都有安全益处。提供铺砌的路肩降低了所有致命事故的风险，并提高了行人和缓慢行驶的车辆的安全性。然而，MTW 用户的安全在铺砌肩宽超过 2 m 的路段上有所降低。此外，铺砌肩宽超过 1.5 m 的路段比没有路肩的路段发生追尾致命事故的风险更高。该研究结果与印度道路当局推荐的几何标准有直接关系。5 m 肩宽。提供铺砌的路肩降低了所有致命事故的风险，并提高了行人和缓慢行驶的车辆的安全性。然而，MTW 用户的安全在铺砌肩宽超过 2 m 的路段上有所降低。此外，铺砌肩宽超过 1.5 m 的路段比没有路肩的路段发生追尾致命事故的风险更高。该研究结果与印度道路当局推荐的几何标准有直接关系。5 m 肩宽。提供铺砌的路肩降低了所有致命事故的风险，并提高了行人和缓慢行驶的车辆的安全性。然而，MTW 用户的安全在铺砌肩宽超过 2 m 的路段上有所降低。此外，铺砌肩宽超过 1.5 m 的路段比没有路肩的路段发生追尾致命事故的风险更高。该研究结果与印度道路当局推荐的几何标准有直接关系。5 m 比没有肩节具有更高的追尾致命碰撞风险。该研究结果与印度道路当局推荐的几何标准有直接关系。5 m 比没有肩节具有更高的追尾致命碰撞风险。该研究结果与印度道路当局推荐的几何标准有直接关系。