Data were obtained from questionnaires completed by 457 drivers in the United Kingdom. Drivers who had experienced frequent accidents and young drivers were deliberately overrepresented in the sample. Respondents indicated how frequently they engaged in each of 26 kinds of traffic violations and considered extensive lists of possible reasons explaining why they engaged in, or refrained from, speeding, running red lights, and driving after drinking. Additional data were obtained from interviews with nearly 300 pub patrons and 110 drivers who had just been stopped for exceeding the speed limit. The drivers interviewed spanned the offending continuum. The findings showed that drivers do have needs -- feelings of control, time, convenience, passengers pressure, mood expression, and pleasure -- which can be served by breaking various traffic laws. They do weigh the opportunities, costs, and benefits of breaking the law, albeit with limited rationality. Only a few of the needs cited by respondents would also be met by non-traffic crime. The results do not necessarily support schemes for the situational prevention of traffic offending; the major obstacles include the high rate of traffic violations, the cognitive choice- structuring properties of traffic offending, and the difficulties in manipulating physical features of the traffic environment. 2 tables, 4 notes, and 21 references