A behavioral inoculation method to improve critical takeover performance of novice drivers in conditionally automated driving.

Objective: The unsafe behaviors and great stress during the critical takeover process cause safety issues in conditionally automated driving. To compensate for the limitations of existing performance improvement methods, the current study aims to reduce unsafe behaviors during the critical takeover process by correcting driver cognitions.

Methods: This study proposed a behavioral inoculation approach against unsafe takeover behaviors. This intervention motivated drivers to refute the incorrect cognition and then form safe behaviors. Two rounds of experiments were conducted. The first round, with 40 participants, was to analyze the unsafe takeover behaviors and select the drivers to intervene. The selected 27 participants were grouped to receive behavioral inoculation, direct instruction, and no training in the second round. The driving tests were conducted in the simulator before, immediately after, and five weeks after the intervention, to evaluate the effect.

Results: Results indicated that driver steering but not braking was the critical unsafe takeover behavior. Behavioral inoculation and direct instruction on unsafe behaviors reduced unsafe steering behaviors and improved brake reaction time. The proposed behavioral inoculation could also relieve stress and minimize individual differences.

Conclusions: This study first proposed a behavioral inoculation method, modified from psychological inoculation, to improve takeover safety. The behavioral inoculation emphasizes practical takeover behaviors and presents the consequence of unsafe behaviors visually to correct wrong cognition of takeover behaviors. These modifications would enhance the inoculation effect of real-time decision-making in dynamic takeover scenarios, providing an effective method to improve takeover performance.