Supplementary data for the paper 'Ipsilateral and contralateral warnings: Effects on decision-making and eye movements in near-collision scenarios'

Cars are increasingly capable of providing drivers with warnings and advice. However, whether drivers should be provided with ipsilateral warnings (signaling the direction to steer towards) or contralateral warnings (signaling the direction to avoid) is inconclusive. Furthermore, how auditory warnings and visual information from the driving environment together contribute to drivers’ responses is relatively unexplored. In this study, 34 participants were presented with animated video clips of traffic situations on a three-lane road, while their eye movements were recorded with an eye-tracker. The videos ended with a near collision in front after 1, 3, or 6 s, while either the left or the right lane was safe to swerve into. Participants were instructed to make safe lane-change decisions by pressing the left or right arrow key. Upon the start of each video, participants heard a warning: Go Left/Right (ipsilateral), Danger Left/Right (contralateral), and nondirectional beeps (Baseline), emitted from the spatially corresponding left and right speakers. The results showed no significant differences in response times and accuracy between ipsilateral and contralateral warnings, although participants rated ipsilateral warnings as more satisfactory. Ipsilateral and contralateral warnings both improved response times in situations in which the left/right hazard was not yet manifest or was poorly visible. Participants fixated on salient and relevant vehicles as quickly as 220 ms after the trial started, with no significant differences between the audio types. In conclusion, directional warnings can aid in making a correct left/right evasive decision while not affecting the visual attention distribution.

汽车如今已愈发能够为驾驶员提供警示与辅助建议。然而，目前尚无定论：究竟应为驾驶员提供同侧警示（ipsilateral warnings，即指示转向方向的警示）还是对侧警示（contralateral warnings，即指示避让方向的警示）。此外，听觉警示与驾驶环境视觉信息如何共同影响驾驶员的反应，这一问题目前仍鲜有研究。本研究共招募34名被试，向其展示三车道道路交通场景的动态视频片段，同时通过眼动追踪仪（eye-tracker）记录其眼动轨迹。视频分别在1秒、3秒或6秒时以前方发生近距离碰撞收尾，此时左侧或右侧车道恰好可供安全变道避让。要求被试通过按下左或右方向键，做出安全的变道避让决策。每段视频开始时，被试会听到来自对应空间位置左右扬声器的三类警示音：一是「左转/右转」（同侧警示，ipsilateral），二是「左侧/右侧危险」（对侧警示，contralateral），三是无指向性蜂鸣音（对照组，Baseline）。实验结果显示：尽管被试认为同侧警示的满意度更高，但同侧与对侧警示在反应时与准确率上均无显著差异。当左侧/右侧危险尚未显现，或可见度较差时，同侧与对侧警示均能有效缩短被试的反应时。被试会在实验开始后最快220毫秒内将视线固定在显著且相关的车辆上，且不同音频类型间的眼动模式无显著差异。综上，方向性警示可辅助驾驶员做出正确的左/右侧避让决策，且不会对视觉注意力分布造成影响。