The inattentive behavior of a driver can also be risk factors for autonomous driving when the driver has to cope with a unexpected situation. However, it is true that we do not have yet sufficient understanding of a user’s experience with the feedback methods for the driver-centered optimal driving condition. This study, the cognitive feedback methods for optimal driving condition by driver state in an autonomous vehicle were compared and prioritized, and the importance of the methods were determined. With the results, the conclusion was reached that a feedback method for maintaining optimal driving condition by driver state may be different by the sensory source on where a feedback method is based: visual, auditory, and haptic. It is believed that this study will be the base for the development of HVI for an autonomous vehicle and accordingly a user’s experience value will be more reflected in developing a human-friendly autonomous vehicle.