Analytical Study on the Visibility of Potential Positions for External Human-Machine Interfaces

2025-07-11

AI Summary

Empirical evidence on optimal placement of external human–machine interface (eHMI) signals on autonomous vehicles remains scarce. Method: This paper proposes a pedestrian-centric visibility assessment framework, implemented via Unity-based multi-scenario simulations. It systematically evaluates the visibility of various front-end vehicle regions—including fenders, headlights, and grilles—from pedestrian viewpoints on sidewalks, under varying vehicle orientations, road geometries, and sight-distance conditions. Contribution/Results: Results demonstrate that the front fender and headlight regions exhibit significantly higher visibility than other front-end components, establishing them as preferred eHMI mounting locations. The study further confirms statistically significant inter-component visibility differences across the vehicle front end. A reusable, visualization-enabled simulation platform is developed, providing quantitative evidence and methodological support for evidence-based eHMI design and deployment.

Technology Category

• Humans and AI: Interaction Techniques and Devices
• Computer Vision: Interpretability, Explainability, and Transparency
• Intelligent Robots: Human-Robot Interaction

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• User Modeling, Personalization and Recommendation: User modeling and simulation for interactive and conversational systems
• Semantics and Knowledge: Data modeling to support human-machine intelligence, including LLMs agents, intelligent system behavior, explanations, and user-friendly interactions

Abstract

As we move towards a future of autonomous vehicles, questions regarding their method of communication have arisen. One of the common questions concerns the placement of the signaling used to communicate with pedestrians and road users, but little work has been published fully dedicated to exploring this. This paper uses a simulation made in the Unity game engine to record the visibility of fifteen different vehicles, specifically regarding the visibility of frontal elements by a pedestrian on the sidewalk. Variables include the vehicle position, number of vehicles on the road, and minimum and maximum distance of the recorded points. It was concluded that the areas of the vehicle most often seen by pedestrians on the sidewalk attempting to cross the road were the frontal frontal fenders and the headlights, with the frontal wheels, frontal doors, bumper, and side mirrors are less visible alternatives. These findings are valuable in the future design of signaling for autonomous vehicles, in order to ensure pedestrians are able to see them on approaching vehicles. The software used provides a platform for similar works in the future to be conducted.

Problem

• Evaluates visibility of autonomous vehicle signaling positions for pedestrians
• Simulates pedestrian perspective on frontal vehicle elements using Unity
• Identifies optimal and suboptimal vehicle locations for external interfaces

Innovation

• Unity simulation for vehicle visibility analysis
• Evaluates frontal fenders and headlights visibility
• Platform for future autonomous vehicle signaling design