In 1971, the Tennessee legislature enacted legislation providing for mandatory jail sentences and driver's license revocations for anyone convicted of driving while intoxicated. This new law had no demonstrable impact on the highway traffic fatalities rate-the intended objective. This paper explores the reasons for this apparent lack of impact. Data suggest that, while there was some increase in the severity of sanctions imposed on drunken drivers, there was still a consistent tendency to suspend the jail sentences and grant drivers restricted driving privileges. Nor is there any reason to believe that the police intensified their efforts to apprehend larger numbers of drunken drivers. Thus, the more severe sanctions threatened in the new law were generally mitigated in practice. Some possible interpretations for this are offered.