Identifying the most comfortable interpersonal distances for autonomous vehicles' passengers

The evolution of autonomous vehicle interiors presents both opportunities and challenges in optimizing space for Non-Driving Related Activities (NDRAs). Previous research explored the reconfiguration of interiors in autonomous vehicles to support key activities such as reading, working, relaxing, and conversing. Building on this foundation, the present study examines how seating arrangements and interpersonal distances influence passenger comfort and conversational quality. Drawing on proxemics theory, the investigation considers the impact of gender, age, and nationality on interpersonal spatial preferences within vehicle cabins. Thirty-seven participants (aged 23-33) experienced three seating configurations -alpha (side-by-side), beta (opposite directions with parallel axes), and gamma (face-to-face)- in a virtual environment developed using Unity and accessed through HoloLens 2. Participants selected their preferred interpersonal distance from five predefined options while interacting in Augmented Reality (AR) with a virtual mannequin. Objective measurements were supplemented with subjective feedback from a post-test questionnaire. This study addresses the following research questions: 1) Which seating configuration is most comfortable for passengers during a conversation? 2) What are the ideal seating distances in each configuration? 3) How does gender influence interpersonal space requirements? 4) How does ethnicity impact interpersonal space preferences? Findings show no significant difference in distances chosen when conversing or not. Distance varied significantly with social relationships. Gender, body size, and culture influenced preferences. Results suggest the need for adaptable interior layouts that can accommodate diverse interpersonal spacing needs.