State Key Laboratory of Automotive Safety & Energy, Department of Automotive Engineering, Tsinghua University, China; Institute for Transport Studies, University of Leeds, UK.
Institute for Transport Studies, University of Leeds, UK.
Accid Anal Prev. 2018 Aug;117:65-74. doi: 10.1016/j.aap.2018.03.034. Epub 2018 Apr 12.
Driver distraction is one of the main causes of motor-vehicle accidents. However, the impact on traffic safety of tasks that impose cognitive (non-visual) distraction remains debated. One particularly intriguing finding is that cognitive load seems to improve lane keeping performance, most often quantified as reduced standard deviation of lateral position (SDLP). The main competing hypotheses, supported by current empirical evidence, suggest that cognitive load improves lane keeping via either increased physical arousal, or higher gaze concentration toward the road center, but views are mixed regarding if, and how, these possible mediators influence lane keeping performance. Hence, a simulator study was conducted, with participants driving on a straight city road section whilst completing a cognitive task at different levels of difficulty. In line with previous studies, cognitive load led to increased physical arousal, higher gaze concentration toward the road center, and higher levels of micro-steering activity, accompanied by improved lane keeping performance. More importantly, during the high cognitive task, both physical arousal and gaze concentration changed earlier in time than micro-steering activity, which in turn changed earlier than lane keeping performance. In addition, our results did not show a significant correlation between gaze concentration and physical arousal on the level of individual task recordings. Based on these findings, various multilevel models for micro-steering activity and lane keeping performance were conducted and compared, and the results suggest that all of the mechanisms proposed by existing hypotheses could be simultaneously involved. In other words, it is suggested that cognitive load leads to: (i) an increase in arousal, causing increased micro-steering activity, which in turn improves lane keeping performance, and (ii) an increase in gaze concentration, causing lane keeping improvement through both (a) further increased micro-steering activity and (b) a tendency to steer toward the gaze target.
驾驶员分神是机动车事故的主要原因之一。然而，认知（非视觉）分神任务对交通安全的影响仍存在争议。一个特别有趣的发现是，认知负荷似乎可以提高车道保持性能，通常表现为横向位置标准差（SDLP）降低。目前的实证证据支持的主要竞争假设表明，认知负荷通过提高身体警觉度或增加对道路中心的注视集中程度来提高车道保持性能，但关于这些可能的中介因素是否以及如何影响车道保持性能，观点不一。因此，进行了一项模拟研究，参与者在直道城市路段驾驶，同时在不同难度水平下完成认知任务。与之前的研究一致，认知负荷导致身体警觉度增加、对道路中心的注视集中程度提高，以及微转向活动水平提高，同时车道保持性能提高。更重要的是，在高认知任务期间，身体警觉度和注视集中程度比微转向活动更早发生变化，而微转向活动又比车道保持性能更早发生变化。此外，我们的结果并未显示个体任务记录中注视集中程度和身体警觉度之间存在显著相关性。基于这些发现，对微转向活动和车道保持性能进行了各种多层次模型的构建和比较，结果表明，现有假设提出的所有机制都可能同时涉及。换句话说，建议认知负荷导致：（i）警觉度增加，引起微转向活动增加，从而提高车道保持性能，以及（ii）注视集中程度增加，通过（a）进一步增加微转向活动和（b）转向注视目标的趋势来提高车道保持性能。
