Abstract
A previous study showed that some drivers felt a haptic display was not enough to inform them of the take-over request（TOR） in a highly automated driving system. This study aimed to verify the result of the previous study after increasing the frequency of haptic stimulus. Thirty drivers participated in a driving simulator experiment to investigate the objective of this study. The driver’s vehicle could automatically adjust the headway distance to a lead vehicle and keep its lateral position in a lane. In automated driving, drivers had to perform a non-driving task and avoid colliding with a stopped vehicle because of automated driving system malfunction. The results of the driving simulator experiment did not produce the same result as the previous study. The results also revealed that the haptic display might induce drivers to look at a frontal road scene before they checked a visual display presented in a car indicator with the haptic one. The human machine interface in highly automated driving was discussed in terms of adequate sensory modalities to inform driver of the take-over request.
