A Longitudinal Simulator Study to Explore Drivers’ Behaviour in Level 3 Automated Vehicles

In a longitudinal study, 49 drivers undertook a commute-style journey, with part of the route supporting level-3 automation, over five consecutive days. Bespoke HMIs were provided to keep drivers in-the-loop during automation, and help them regain situational-awareness (SA) during handovers, in a 2×2 between-subjects design. Drivers demonstrated high levels of trust from the outset, delegating control to the vehicle (when available) and directing attention to their own activities/devices. Ratings of trust and technology acceptance increased during the week – even following an unexpected, emergency handover on day four – with the highest ratings recorded on day five. High levels of lateral instability were observed immediately following take-overs, although improvements were noted during the week and following the provision of SA-enhancing hand-over advice. Results demonstrate benefits associated with novel HMI designs to keep drivers in-the-loop and improve take-over performance, as well as the necessity of multiple exposures during the evaluation of future, immersive technologies.