Exploring the Impacts of Background Noise on Auditory Stimuli of Audio-Visual eHMIs for Hearing, Deaf, and Hard-of-Hearing People

2026-01-19

AI Summary

This study addresses the unclear impact of background noise on how individuals with hearing impairments, those who are hard of hearing, and those with typical hearing perceive auditory signals in external human–machine interfaces (eHMIs) for automated vehicles, highlighting a critical gap in inclusive research for vulnerable road users. Through virtual reality experiments conducted in both quiet and noisy environments, the research systematically evaluates three types of auditory cues—baseline tones, chimes, and speech—on pedestrians’ crossing experiences. It reveals, for the first time, significant differences between hearing-impaired and typically hearing individuals in eHMI interactions, demonstrating that high ambient noise degrades user experience, whereas incorporating chimes or speech substantially enhances crossing confidence and perceived safety. These findings provide empirical support and practical guidance for designing inclusive eHMIs.

Technology Category

• Humans and AI: AI for Accessibility
• Intelligent Robots: Human-Robot Interaction
• Cognitive Modeling & Cognitive Systems: Affective Computing

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• User Modeling, Personalization and Recommendation: Practical large-scale studies of user experience
• Security and Privacy: Large-scale security measurements

Abstract

External Human-Machine Interfaces (eHMIs) have been proposed to enhance communication between automated vehicles (AVs) and pedestrians, with growing interest in multi-modal designs such as audio-visual eHMIs. Just as poor lighting can impair visual cues, a loud background noise may mask the auditory stimuli. However, its effects within these systems have not been examined, and little is known about how pedestrians -- particularly Deaf and Hard-of-Hearing (DHH) people -- perceive different types of auditory stimuli. We conducted a virtual reality study (Hearing N=25, DHH N=11) to examine the effects of background noise (quiet and loud) on auditory stimuli (baseline, bell, speech) within an audio-visual eHMI. Results revealed that: (1) Crossing experiences of DHH pedestrians significantly differ from Hearing pedestrians. (2) Loud background noise adversely affects pedestrians'crossing experiences. (3) Providing an additional auditory eHMI (bell/speech) improves crossing experiences. We outlined four practical implications for future eHMI design and research.

Problem

• background noise
• auditory stimuli
• audio-visual eHMI
• Deaf and Hard-of-Hearing
• pedestrian communication

Innovation

• audio-visual eHMI
• background noise
• Deaf and Hard-of-Hearing (DHH)
• virtual reality study
• auditory stimuli