The present study was to identify specific characteristics of motor vehicle drivers that are associated with traffic accident. When driver's age and the length of driving experience were controlled for through analysis of covariance, the group differences remained on such factors as Carefulness, Regulation Observance, Responsibility, and the total score of SDAT. When different age groups among the bus drivers were compared to one another, the drivers in 50's showed higher scores than those in 30's and 40's on the factors of Carefulness and Driving Attitude. When different age groups among the accident repeaters were compared to one another, the drivers in 50's showed higher scores than those in 30's and 40's on all of the factors. Regulation offenders did not differ from unwitting victims on the scale scores of MMPI. However, the number of offense was a function of Schizophrenia score among the offenders. The drivers with less driving experience showed higher scores than did the drivers with more driving experience on Masculinity-Femininity, Paranoia, Schizophrenia, and Hypomania scales of MMPI.