Factors related to the road infrastructure contribute to the occurrence of motorcycle accidents. This study investigates how design parameters of the existing rural two-lane road network in Norway influence the occurrence of single motorcycle accidents. The design elements considered in this study are horizontal curvature (curve type, degree of curvature, and adjacent curve requirements) and lane and shoulder widths. A matched case-control study design was applied to investigate the safety effects of these elements. Cases were defined as segments experiencing at least one single motorcycle accident during the study period from 2013 to 2017, while controls were defined as segments not experiencing an accident in the same period. In order to identify the segments, a GIS analysis was performed on data collected from the National Road Database (NVDB). In case-control studies, matching allows us to control for confounding variables. AADT and speed limit were used as matching variables in this study. A matching ratio of 4 : 1 (i.e., four controls per case) was used, resulting in 752 controls being matched to 188 cases. The results indicate horizontal alignment to have a more significant effect on single motorcycle accidents compared to lane and shoulder widths. Segments with several adjacent reverse curves, with high curvature (R < 200 m), have high odds for an accident. Further, if the requirements for adjacent curves are not fulfilled (i.e., considerable variation in adjacent curve radii), the odds increase even more. While the results are not statistically significant, trends seen indicate that wider lanes were associated with increased odds for an accident, while wider shoulders were associated with decreased odds. In comparison with a similar study considering passenger vehicles, the results of this study also indicate that horizontal alignment has a greater effect on single motorcycle accidents than on passenger vehicle accidents.

中文翻译：

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水平曲线设计和车道和肩宽对挪威单摩托车事故的安全影响

与道路基础设施有关的因素导致摩托车事故的发生。这项研究调查了挪威现有的农村两车道公路网络的设计参数如何影响单摩托车事故的发生。本研究中考虑的设计元素是水平曲率（曲线类型，曲率度和相邻曲线要求）以及车道和路肩宽度。匹配的病例对照研究设计用于调查这些元素的安全效果。病例定义为在2013年至2017年的研究期间发生至少一次摩托车事故的人群，而对照组则定义为同期未发生任何摩托车事故的人群。为了识别路段，对从国道数据库（NVDB）收集的数据进行了GIS分析。在案例对照研究中，匹配使我们能够控制混杂变量。在这项研究中，AADT和限速被用作匹配变量。使用4：1的匹配率（即，每例四个对照），从而使752个对照与188个病例匹配。结果表明，与车道和路肩宽度相比，水平对齐对单摩托车事故的影响更大。具有多个相邻反向曲线且曲率高的线段（结果表明，与车道和路肩宽度相比，水平对齐对单摩托车事故的影响更大。具有多个相邻反向曲线且曲率高的线段（结果表明，与车道和路肩宽度相比，水平对齐对单摩托车事故的影响更大。具有多个相邻反向曲线且曲率高的线段（R  <200 m），发生事故的几率很高。此外，如果不满足相邻曲线的要求（即，相邻曲线半径的显着变化），则几率甚至更大。虽然结果在统计上不显着，但趋势表明，较宽的车道与事故几率增加相关，而较宽的路肩与几率降低有关。与考虑乘用车的类似研究相比，该研究的结果还表明，水平对准对单摩托车事故的影响要大于对乘用车事故的影响。