Tactical-Level Explanation is Not Enough: Effect of Explaining AV’s Lane-Changing Decisions on Drivers’ Decision-Making, Trust, and Emotional Experience

Abstract

Explanations have become increasingly vital in communicating with human drivers about the reasons for the decision-making of autonomous vehicles (AVs), particularly in tactical-level driving tasks. Focusing on lane-changing scenarios, we examine whether providing tactical-level explanations and in addition, whether providing a confirmation option, influences drivers’ decision-making, trust, and emotional experience. Thirty participants were equally assigned into three groups: indicator (I), explanation (E), and explanation + confirmation (EC), experiencing four lane-changing scenarios in a driving simulator. Real-time question probes and interviews were adopted to understand drivers’ decision-making process, and post-drive questionnaires on trust and emotional experience were given. Results indicated that merely providing tactical-level explanations had little effect on driver’s trust and experience, but caused worse decision-making performance. The option to confirm lane changes after an explanation promoted driver’s trust, but brought two-sided effects on decision-making performance. Situational trust and decision-making performance varied significantly across lane-changing scenarios.