Key Laboratory of Road and Traffic Engineering, Ministry of Education, Tongji University, Shanghai, China; Engineering Research Center of Road Traffic Safety and Environment, Ministry of Education, Tongji University, Shanghai, China.
Key Laboratory of Road and Traffic Engineering, Ministry of Education, Tongji University, Shanghai, China.
Accid Anal Prev. 2019 Jun;127:80-86. doi: 10.1016/j.aap.2019.02.020. Epub 2019 Mar 2.
Road geometric design is a fundamental factor that impacts driving speed. Previous research generally paid attentions to the influences of specific road characteristics (e.g. curvature) on driving behaviors. Limited studies have focused on how drivers identify different alignments and how they further take the varying speed choices. This study aims at filling the gap by investigating the subjective categorization of road alignments based on middle-aged driver groups. A total of sixteen participants with ages ranging from 23 to 40 years were recruited. Participants were first asked to undertake naturalistic driving tests on a four-lane divided mountainous freeway while photos of the road and the driving speed were collected. Participants were then asked to subjectively sort the photos of the road into piles, within each pile we considered their driving behaviors would be similar. Finally, questionnaire survey was conducted in terms of comfort, safety, speed choice and sight distance. The picture grouping revealed three distinct and non-overlapping subjective categories of road alignment. And driver's ratings about comfort and safety were significantly different between these categories. The category with the largest sight distance and highest speed choice turned out to have the lowest rating in comfort and safety (note that the rating scales for comfort and safety had reversed polarity such that low numbers indicated high comfort and high safety). Statistical evidences indicated that the drivers have developed underlying mental schema about road alignment. Therefore, their speed choices on combined alignment were further investigated. The difference between actual driving speed and driver's expected speed showed close relation to the ratings and significant difference between two of the categories. Road with large absolute value in speed difference informed inconsistency between geometric design and driver's expectation from the aspects of drivers' perception and expectation of the road. The findings provided insight into how middle-aged driver views and categorizes road alignment. And it was found that the drivers relied on visual characteristics of the alignment to distinguish the categories instead of separate horizontal and vertical geometric parameters. It was implied that more considerations should be taken into driver's perception of road during alignment design to improve road safety.
道路几何设计是影响驾驶速度的一个基本因素。以往的研究通常关注特定道路特征（如曲率）对驾驶行为的影响。有限的研究集中在驾驶员如何识别不同的路线以及他们如何进一步选择不同的速度。本研究旨在通过调查基于中年驾驶员群体的道路路线的主观分类来填补这一空白。共招募了 16 名年龄在 23 岁至 40 岁之间的参与者。参与者首先在四车道分向山区高速公路上进行自然驾驶测试，同时收集道路和驾驶速度的照片。然后，要求参与者将道路的照片主观地分成几堆，每一堆我们认为他们的驾驶行为将是相似的。最后，就舒适性、安全性、速度选择和视距进行问卷调查。图片分组显示了道路路线的三个明显且不重叠的主观类别。并且，这些类别之间驾驶员对舒适性和安全性的评价有显著差异。视距最大和速度选择最高的类别在舒适性和安全性方面的评价最低（请注意，舒适性和安全性的评价量表具有相反的极性，即数字越低表示舒适性和安全性越高）。统计证据表明，驾驶员已经对道路路线形成了潜在的心理模式。因此，进一步研究了他们在组合路线上的速度选择。实际驾驶速度与驾驶员预期速度之间的差异与评价以及两个类别之间的显著差异密切相关。速度差异的绝对值较大的道路表明，从驾驶员对道路的感知和期望方面来看，几何设计与驾驶员的期望之间存在不一致性。研究结果深入了解了中年驾驶员如何看待和分类道路路线。并且发现驾驶员依赖于路线的视觉特征来区分类别，而不是单独的水平和垂直几何参数。这意味着在路线设计时应更多地考虑驾驶员对道路的感知，以提高道路安全性。
