Effects of Time Headway on Driving after Prolonged Automation Exposure: Evidence for Behavioral Adaptation

The shift of a driver’s role from an active operator to a passive supervisor of an automated vehicle (AV) can result in adverse behavioral adaptation effects (BAEs). Prior studies showed that after drivers were exposed to an AV that adopts an extremely small time headway for a prolonged duration, drivers adopted shorter time headways than what they would normally use. However, the effect of an AV’s headway on BAEs has not been examined. The current study conducted two experiments to determine whether (a) the effect of exposure duration (15, 25 min) on a driver’s headway post-automation depends on AVs’ headways (0.3 s, 0.6 s), and (b) a driver’s trust in the AV varies with AVs’ headways (0.3 s, 0.6 s, 1.5 s). Results revealed that trust was positively correlated with AV headway and a significant number of drivers reduced their headways after regaining control of the vehicle, a result consistent with prior BAE research.