Towards Adaptive External Communication in Autonomous Vehicles: A Conceptual Design Framework

TL;DR

This paper proposes a conceptual framework for adaptive external communication interfaces in autonomous vehicles, aiming to improve interaction with road users through dynamic, context-aware signaling.

Contribution

It introduces a structured, three-layer framework for designing and analyzing adaptive eHMIs, addressing scalability and inclusivity issues in current systems.

Findings

Framework facilitates systematic design of adaptive eHMIs

Addresses limitations of reactive communication systems

Raises ethical and technical considerations for implementation

Abstract

External Human-Machine Interfaces (eHMIs) are key to facilitating interaction between autonomous vehicles and external road actors, yet most remain reactive and do not account for scalability and inclusivity. This paper introduces a conceptual design framework for adaptive eHMIs-interfaces that dynamically adjust communication as road actors vary and context shifts. Using the cyber-physical system as a structuring lens, the framework comprises three layers: Input (what the system detects), Processing (how the system decides), and Output (how the system communicates). Developed through theory-led abstraction and expert discussion, the framework helps researchers and designers think systematically about adaptive eHMIs and provides a structured tool to design, analyse, and assess adaptive communication strategies. We show how such systems may resolve longstanding limitations in eHMI research while raising new ethical and technical considerations.