This paper presents the results of real-world testing of human-vehicle interactions with an autonomous vehicle equipped with internal and external Human Machine Interfaces (HMIs) in a crosswalk scenario. The internal and external HMIs were combined with implicit communication techniques using gentle and aggressive braking maneuvers in the crosswalk. Results have been collected in the form of questionnaires and measurable variables such as distance or speed when the pedestrian decides to cross. The questionnaires show that pedestrians feel safer when the external HMI or the gentle braking maneuver is used interchangeably, while the measured variables show that external HMI only helps in combination with the gentle braking maneuver. The questionnaires also show that internal HMI only improves passenger confidence in combination with the aggressive braking maneuver.

翻译：本文报告了配备内外部人机界面（HMI）的自动驾驶汽车在真实人行横道场景中进行的人车交互测试结果。内外部HMI与隐式通信技术相结合，在人行横道处分别采用缓和及激进制动策略。通过问卷调查及行人决策横穿时的距离、速度等可测量变量收集数据。问卷结果表明，当交替使用外部HMI或缓制动策略时，行人安全感更高；而可测变量显示外部HMI仅在与缓制动策略配合时有效。问卷还表明，内部HMI仅在激进制动策略配合下能提升乘客信心。