This study examined the association between psychosocial maturation and problem driving behavior in young adulthood. Psychosocial maturation is the process of adopting adult roles, attitudes and behaviors and completing developmental tasks associated with becoming an adult. Past research has demonstrated that individuals' participation in health-risk behaviors decreases as psychosocial maturity increases. Not Surprisingly, decreases in driving risk that occur over the first years of driving have often been assumed to result in large degree from general maturation; however, no research has tested this assumption. This Study used data from a telephone survey of young adults to begin addressing this gap in the literature by testing three hypotheses: (1) indicators of higher psychosocial maturity are associated with lower problem driving behavior: (2) the association between the level of psychosocial maturity and problem driving behavior is cumulative: and, (3) these associations are moderated by sex. Problem driving behavior was evaluated by assessing three measures: high-risk driving, drink/driving, and drug/driving. Results supported all three hypotheses. Participants with greater psychosocial maturity had lower levels of problem driving behavior than participants who were less psychosocially mature. Second, problem driving behavior was lower with higher psychosocial maturity. Third, these associations between psychosocial maturity and problem driving behavior were moderated by sex. The primary contributions of this study are: (I) initial evidence that psychosocial maturation may play a role in improvements in the safety of young drivers; and (2) the generation of questions and hypotheses that provide direction for future research on the role Of maturation in observed declines in risk among young drivers. (C) 2008 Elsevier Ltd. All Fights reserved.