Psycho-physiological parameters to evaluate the mental demand during driving

The aim of this study was to develop parameters that could evaluate the driver's psycho-physiological response to road design during highway driving. A hypothesis was made such that people could drive safely if they had a proper level of `mental effort' that could cover the `mental demand' required by driving environment. This matching value of demand and effort was named as a `demand-effort matching profile (DEMP)' in this study. In order to find psycho-physiological parameters satisfying DEMP in various road conditions, the mental `demand' of the road environment was categorized into three: high, moderate, low demand. Seventy subjects participated in the experiment to measure the mental `effort' during driving the vehicle equipped with measuring devices. 48 psycho-physiological parameters were examined in this study, and the parameters with consistent DEMP were summarized in this study. Those parameters could be used for further investigation of the relationship between drivers and road design.