Abstract
A user's trust in an automatic system is important for application of the system. The trust is not yet, however, measured in the pervious researches on driver assist systems which are automatic systems in ITS. In this paper, we conduct the driving simulator experiment for the low-speed ACC system as one of the driver assist systems and measure the trust of the drivers. Consequently, the followings are clarified : The trust varies dynamically and it is reduced by generating of a temporary system error. The trust is recovered by continuing a normal run, and the variation becomes small.
