To Takeover or Not to Takeover? The Role of Drivers’ Trust in Influencing Time Spent in Manual Versus Automated Driving

Drivers’ trust in conditionally automated vehicles (AVs) is a critical concept affecting voluntary takeover behavior. However, few studies have examined how long drivers manually control an AV before re-activating the automation as a function of their level of trust. This study investigated the distribution of time in manual versus automated driving modes between drivers with low and high trust (1) in the absence of a takeover request and (2) when system reliability was unknown to drivers. Fifty participants were assigned to either a high- or low-trust induction phase through a video and practice drive, followed by the same main driving scenario. Drivers in the low-trust group spent significantly more time manually controlling the AV and delayed returning control to the AV compared to those in the high-trust group. Findings have implications for the design of intelligent in-vehicle systems that could aid drivers in determining when to use vehicle autonomous features.