This paper reports results from a high-fidelity driving simulator study (N=215) about a head-up display (HUD) that conveys a conditional automated vehicle's dynamic "uncertainty" about the current situation while fallback drivers watch entertaining videos. We compared (between-group) three design interventions: display (a bar visualisation of uncertainty close to the video), interruption (interrupting the video during uncertain situations), and combination (a combination of both), against a baseline (video-only). We visualised eye-tracking data to conduct a heatmap analysis of the four groups' gaze behaviour over time. We found interruptions initiated a phase during which participants interleaved their attention between monitoring and entertainment. This improved monitoring behaviour was more pronounced in combination compared to interruption, suggesting pre-warning interruptions have positive effects. The same addition had negative effects without interruptions (comparing baseline & display). Intermittent interruptions may have safety benefits over placing additional peripheral displays without compromising usability.

翻译：本文报告了一项高保真驾驶模拟器研究（N=215）的结果，该研究涉及一种抬头显示（HUD），用于在备用驾驶员观看娱乐视频时，传递条件自动化车辆对当前情境的动态"不确定性"。我们比较了（组间）三种设计干预措施：显示（视频附近的不确定性条形可视化）、中断（在不确定情况下中断视频）以及组合（两者结合），并与基线条件（仅视频）进行对比。我们对眼动追踪数据进行可视化，对四组随时间变化的注视行为进行了热图分析。我们发现中断启动了一个阶段，在此阶段参与者在监控和娱乐之间交替分配注意力。与单独中断相比，组合条件下的监控行为改善更为显著，这表明预警中断具有积极效果。在没有中断的情况下，相同的附加显示产生了负面影响（比较基线与显示条件）。间歇性中断可能比增加外围显示具有安全优势，且不会损害可用性。