Pedestrians rely on vehicle dynamics, engine sound, and driver cues. The lack of engine sound now constitutes an addressed pedestrian safety issue for (hybrid) electric vehicles ((H)EVs). Analogously, lacking driver cues may constitute a pedestrian safety issue for self-driving vehicles (SDVs). The purpose of this study was to systematically compare the relevance of substituting driver cues with an external human-machine interface among SDVs (no eHMI vs. eHMI) with the relevance of substituting engine sound with artificial sound among (H)EVs (no engine sound vs. engine sound). In a within-subject design, twenty-nine participants acting as pedestrians encountered a simulated SDV in a parking lot. The results revealed that both informational cues have equally large effects on subjective measures such as perceived safety. In semi-structured interviews, participants stated that it is equally crucial to equip SDVs with an eHMI as equipping (H)EVs with an artificial sound generator. We conclude that an eHMI for SDVs seems to be as relevant as an artificial sound for (H)EVs.

行人依赖于车辆动力学、发动机声音和驾驶员提示。对于（混合动力）电动汽车 ((H)EV) 而言，发动机声音的缺失现在构成了一个解决的行人安全问题。类似地，缺乏驾驶员提示可能构成自动驾驶汽车 (SDV) 的行人安全问题。本研究的目的是系统地比较 SDV（无 eHMI 与 eHMI）之间用外部人机界面替换驾驶员提示的相关性与（H）EV（无发动机声音）中用人工声音替换发动机声音的相关性。与发动机声音）。在主体内设计中，作为行人的 29 名参与者在停车场遇到了模拟 SDV。结果表明，这两种信息线索对主观测量（例如感知安全性）具有同样大的影响。在半结构化访谈中，参与者表示，为 SDV 配备 eHMI 与为 (H)EV 配备人工发声器同等重要。我们得出的结论是，SDV 的 eHMI 似乎与 (H)EV 的人工声音一样相关。