Trust in automated mobility as a social process: Behavioural and conversational evidence from shared rides

Abstract

Trust is a critical determinant of public acceptance of automated vehicles, particularly in shared mobility contexts where passengers co-experience automation. While prior research has largely examined trust as an individual judgement, emerging shared automated mobility raises the need to understand how trust unfolds within groups and across different sources of driving agency. This study investigates how situational urgency and driving agency (human vs. automated control) shape trust during shared rides. Thirty-six participants completed a within-subjects virtual reality (VR) study in triads, experiencing automated and manual driving under low- and high-urgency scenarios. Trust was assessed using a multi-method approach combining real-time behavioural signals (press-and-hold trust-loss input), post-trial questionnaires, and thematic analysis of group conversations. Results show that trust was lowest in automated low-urgency scenarios and highest in manual high-urgency scenarios, suggesting that perceived agency strongly shapes trust calibration. Button-press behaviour captured moment-to-moment trust breakdowns and correlated with subjective trust ratings, supporting its validity as a real-time indicator. Qualitative findings reveal that trust was socially situated, with group sense-making processes shaping how passengers interpreted vehicle behaviour, situational ambiguity, and control attribution. Together, the findings position trust in automated mobility as a socially embedded and context-dependent phenomenon, and highlight the importance of designing shared automated vehicle (AV) systems that support real-time trust expression and collective understanding.