Pedestrian interaction with multiple highly automated vehicles: Effects of LED- and augmented reality eHMIs

Wilbrink, Marc; Oehl, Michael · 2026 · openalex_search

DOI: 10.1016/j.trf.2026.103560

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Summary

This study investigates how external human-machine interfaces (eHMIs) affect pedestrian interactions with highly automated vehicles (HAVs) in complex urban environments. The research addresses the communication gap created by the absence of human drivers, who traditionally provide explicit cues like eye contact. While light-based eHMIs are established, their effectiveness in complex scenarios with multiple vehicles is unclear, and the potential of Augmented Reality (AR) and multimodal combinations remains underexplored. The authors hypothesized that AR and combined LED+AR interfaces would improve crossing initiation times, perceived safety, and understandability while reducing mental workload compared to no eHMI or LED-only conditions. The researchers conducted a within-subject experiment using a Virtual Reality (VR) simulation of a shared space environment. Forty participants encountered HAVs approaching from both sides under four eHMI conditions: no eHMI, a 360° LED light band, an AR interface projecting the vehicle’s trajectory and stopping position, and a combined LED+AR setup. The study also varied vehicle kinematics across four levels, including scenarios where both vehicles yielded, only one yielded, or neither yielded. Objective measures included crossing initiation time, while subjective measures assessed perceived safety, mental workload (NASA-TLX), understandability, and predictability. Data were analyzed using repeated-measures ANOVAs. Results indicated that communicating HAV intentions via LED or AR significantly improved crossing initiation time, perceived safety, and understandability, while reducing mental workload compared to the no-eHMI baseline. AR outperformed the LED condition in these metrics. Crucially, the combined LED+AR interface preserved the benefits of AR without increasing mental workload, confirming that multimodal design does not induce cognitive overload. These benefits remained stable regardless of the specific vehicle kinematics or yielding patterns. The study demonstrates that AR enhances eHMI effectiveness by providing spatially embedded, targeted information, while the combination with LEDs ensures inclusivity for non-AR users. These findings support the development of multimodal eHMIs to facilitate safe, intuitive, and confident pedestrian interactions in future automated urban environments.

Key finding

Augmented reality-based eHMIs outperformed LED-only systems in improving pedestrian crossing initiation times and perceived safety, while a combined LED and AR interface maintained these benefits without increasing mental workload.

Methodology

simulator

Sample size: 40

Provenance

The full processing record for this entry. Every stage of this paper's journey through the pipeline is logged — what ran, with which tool and model, how many attempts it took, and when it last completed. Discovered via scout_discovery on 2026-05-08 (3 acquisition events logged).

Summary generated by qwen3.6-27b-prismaquant on 2026-06-10; verification: verified_with_issues.

Topics

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• vru facing ehmi
• ehmi external hmi
• hud ar windshield
• automation

Information type

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• Applied Guidance: design guidelines