Abstract
A method to measure a driver's mental and physical load directly has been considered as an effective tool for the development of a comfortable and safe vehicle, and attempts have been made to use various physiological reactions as objects. This paper reports on one method which uses
'Heart Rate Variability (HRV)'. Reason of using HRV has already been reported by some research institutes. In this study, the method of calculating HRV has been improved for use in the analysis of a driver's heartbeat during driving, and the potential of HRV as a tool to quantify a driver's tension and fatigue has been confirmed experimentally.