Impact of eHMI on Pedestrians' Interactions with Level-5 Automated Driving Systems

2025-07-28

AI Summary

This study investigates how external human–machine interfaces (eHMIs) influence pedestrian interaction with Level 5 automated driving systems (ADS), focusing on improving pedestrians’ comprehension of vehicle intent, perceived safety, and trust. Method: A mixed-method approach combining online surveys and scenario-based simulations was employed to systematically compare visual eHMIs (e.g., textual cues, external speedometers) against auditory eHMIs. Contribution/Results: Visual eHMIs significantly enabled earlier and more confident pedestrian crossing decisions and outperformed auditory cues in enhancing intent understanding, perceived safety, and trust. In multimodal configurations, the visual modality dominated behavioral and cognitive outcomes. This work provides the first empirical validation of the primacy of visual eHMIs in Level 5 ADS–pedestrian interaction, establishing evidence-based priorities for eHMI standardization and informing safer, human-centered design of automated vehicle interfaces.

Technology Category

• Humans and AI: Interaction Techniques and Devices
• Intelligent Robots: Human-Robot Interaction
• Cognitive Modeling & Cognitive Systems: Simulating Human Behavior

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• Economics, Online Markets and Human Computation: Humans versus LLMs for data annotation and labeling
• Semantics and Knowledge: Data modeling to support human-machine intelligence, including LLMs agents, intelligent system behavior, explanations, and user-friendly interactions

Abstract

Each year, over half of global traffic fatalities involve vulnerable road users (e.g. pedestrians), often due to human error. Level-5 automated driving systems (ADSs) could reduce driver errors contributing to pedestrian accidents, though effectiveness depends on clarity and understandability for other road users. External human-machine interfaces (eHMIs) have been proposed to facilitate pedestrian-ADS communication, though consensus on optimal eHMI features remains unclear. In an online survey, 153 participants responded to road-crossing scenarios involving level-5 ADSs, with and without eHMIs. With eHMIs, pedestrians crossed earlier and more confidently, and reported significantly increased perceptions of safety, trust, and understanding when interacting with level-5 ADSs. Visual eHMI features (including a text display and external speedometer) were ranked more necessary than auditory ones, though auditory cues received positive feedback. This study demonstrates that eHMIs can significantly improve pedestrians' understanding of level-5 ADS intent and enhance perceived safety and trust, facilitating more intuitive pedestrian-ADS interactions.

Problem

• How eHMIs improve pedestrian safety with Level-5 ADS
• Optimal eHMI features for pedestrian-ADS communication
• Impact of visual vs auditory eHMI cues on trust

Innovation

• eHMIs enhance pedestrian-ADS communication clarity
• Visual eHMI features preferred over auditory cues
• eHMIs increase pedestrian safety trust and understanding