The authors review the literature pertaining to the roles of psychopathology and personality variables in traffic accidents. They review studies of nonpsychiatric and psychiatric samples and examine the roles of suicide, life events, alcohol, and drugs. Certain personality characteristics and psychopathology--such as low tension tolerance, immaturity, personality disorder, and paranoid conditions--appear to be risk factors for traffic accidents. Although the role of alcohol is relatively well established, the roles of most other drugs are less clear. The results of further investigation of psychopathology's role in traffic accidents may have implications for prevention.