In 1988, the Minnesota Legislature enacted a law requiring that when a drunk driver is arrested a third or subsequent time, license plates of all his vehicles shall be impounded and destroyed. From August 1988 through December 1990, the law was administered through the court system, then amended to parallel the State's administrative per se law: the arresting officer issues the impoundment order at the time of arrest. Survival analysis is used to compare recidivism of violators in three treatment and two comparison groups. There is no evidence that the judge's impoundment order, during the court-based phase of the law, had any significant impact on violator recidivism. After the law became administrative, violators who received impoundment orders recidivated significantly less than those who did not. Thus, the author concludes that evidence suggests that license plate impoundment is a practical countermeasure that can play a part in helping to reduce the impaired-driver problem. Tables, references