Abstract
No perceived fatigue or lower fatigue degree is one of the requirements of seating comfort. Quantitative evaluations of physical and mental loads are effective in developing more human-friendly vehicles. In this paper, a human-automobile interface model was built to explain the reasons of driver fatigue and vigilance task was used for simulating driver mental load. The evaluation of driver fatigue was focused on mental fatigue. As a result, CFF and HRV were good indices for quantitative evaluation of mental load and driver fatigue.