Effects of dual-message tactile sliding takeover requests on takeover performance in an automated driving system.

Objective: The present study aimed to explore the effects of various tactile takeover requests (TORs) (i.e., tactile sliding TOR and traditional vibration TOR) on the takeover performance in an automated driving system.

Methods: A tactile sliding motor device was developed to signal the sliding TOR on the seatback of a driving simulator. Twenty-five young drivers were recruited as participants. Four types of TOR patterns were adopted in the study: ipsilateral motor rotation (IR), contralateral motor rotation (CR), ipsilateral and contralateral motor rotation (ICR), and ipsilateral motor vibration (IV). The participants were required to sit on the seat and underwent the automated driving in a low- or high-complexity scenario, then one of the four types of TORs was triggered randomly. The participants were asked to make a lane change using the steering wheel as soon as possible. Objective measures and subjective evaluations were used to assess the takeover performance.

Results: Results showed that the participants exhibited a shorter steering response time and lane change time under the three tactile sliding TORs (compared to the traditional vibration TOR). In the high-complexity scenarios and low-complexity scenarios conditions, different result patterns appeared regarding the maximum lateral acceleration and situational awareness.

Conclusion: Our findings suggested that the tactile sliding motor is a promising way to signal a TOR in an automated driving system.