  The purpose of this paper is to develop a shared control takeover strategy
for smooth and safety control transition from an automation driving system to
the human driver and to approve its positive impacts on drivers' behavior and
attitudes. A "human-in-the-loop" driving simulator experiment was conducted to
evaluate the impact of the proposed shared control takeover strategy under
different disengagement conditions. Results of thirty-two drivers showed shared
control takeover strategy could improve safety performance at the aggregated
level, especially at non-driving related disengagements. For more urgent
disengagements caused by another vehicle's sudden brake, a shared control
strategy enlarges individual differences. The primary reason is that some
drivers had higher self-reported mental workloads in response to the shared
control takeover strategy. Therefore, shared control between driver and
automation can involve driver's training to avoid mental overload when
developing takeover strategies.
