Driving is a complex behavior that can be affected by an individual's emotional and cognitive status, and the environment. Since a neuropsychological approach is useful in identifying the complex combination of factors that may cause risky driving behaviors, and because subjective perceptions may misguide the decision-making process, this approach based on brain wave indexes was examined. The merit of this approach is that it enables any member to make decisions regarding an individual's ability to drive, despite insufficient information. First, we used a questionnaire survey to identify "risky drivers" and the relationship between traffic accidents and the drivers' psychosomatic state before traffic accidents. As a result, we found that risky drivers, who made up only 13.6% of respondents, accounted for 56.2% of the total number of accidents. We identified the "risky psychosomatic state" related to the risky driving behaviors. Finally, we proposed a direction for research concerning the neuropsychological approach based on brain wave indexes. These results can be incorporated into advanced driving support systems that grasp the driving environment, control the driver's psychosomatic state to alleviate his risky psychological traits, and intervene to handle the car inappropriately.