Supplementary data for the paper 'Immersive Insights: Evaluating Augmented Reality Interfaces for Pedestrians in a CAVE-Based Experiment'

Introduction: Augmented reality (AR) has been increasingly studied in transportation, particularly for drivers and pedestrians interacting with automated vehicles (AVs). Previous research evaluated AR interfaces using online video-based questionnaires but lacked human-subject research in immersive environments. This study examined if prior online evaluations of nine AR interfaces could be replicated in an immersive virtual environment and if AR design effectiveness depends on pedestrian attention allocation. Methods: Thirty participants completed 120 trials in a CAVE-based simulator with yielding and non-yielding AVs, rating interface intuitiveness and crossing the road when feeling safe. To emulate visual distraction, participants had to look into an attention-attractor circle that disappeared 1 s after the interface appeared. Results: The results showed that intuitiveness ratings from the current CAVE-based study and the previous online study correlated strongly (r ≈ 0.90). Head-locked interfaces and familiar designs (augmented traffic lights, zebra crossing) yielded higher intuitiveness scores and quicker crossing initiations than vehicle-locked interfaces. Vehicle-locked interfaces were less effective when the attention-attractor was on the environment’s opposite side, while head-locked interfaces were relatively unaffected by attention-attractor position. Discussion: In conclusion, this ‘AR in VR’ study shows strong congruence between intuitiveness ratings in a CAVE-based study and online research, and demonstrates the importance of interface placement in relation to user gaze direction.

引言：增强现实（AR）在交通领域的研究日益增多，尤其聚焦于驾驶员与行人同自动驾驶汽车（AVs）的交互场景。既往研究多通过基于在线视频的问卷对AR界面进行评估，但缺乏沉浸式环境下的人类被试研究。本研究旨在验证两个核心问题：其一，能否在沉浸式虚拟环境中复现此前针对9种AR界面的在线评估结果；其二，AR界面的设计有效性是否取决于行人的注意力分配情况。

研究方法：30名被试在洞穴式虚拟仿真（CAVE）模拟器中完成了120次试验，试验涵盖让行与不让行的自动驾驶汽车场景，被试需对界面直观性进行评分，并在确认安全时发起过马路动作。为模拟视觉干扰，被试需注视一个注意力吸引环，该环会在AR界面出现1秒后消失。

研究结果：结果显示，本次CAVE研究与既往在线研究的界面直观性评分呈现强相关性（相关系数r≈0.90）。头部锁定界面以及熟悉的设计（如增强型交通灯、斑马线）相比车辆锁定界面，可获得更高的直观性评分，且能更快触发过马路动作。当注意力吸引环位于场景对侧时，车辆锁定界面的有效性有所降低，而头部锁定界面则基本不受注意力吸引环位置的影响。

讨论：综上，本项“虚拟环境下的增强现实”研究表明，CAVE模拟器研究与在线研究的界面直观性评分具有高度一致性，同时证实了界面布局与用户注视方向之间的关联至关重要。