Banner-Evaluation of Minnesota's High-BAC Law

3. Evaluation of Minnesota's High-BAC Law

Profile and Disposition of DWI Cases 1997-2000

In this chapter, the term “DWI offense” refers to a DWI arrest that resulted in a pre-conviction administrative sanction, a post-conviction court sanction, or both, according to the Department of Public Safety driver license records. In late spring 2000, data on DWI offenses were extracted from the driver license file of the Minnesota Department of Public Safety. A data record was provided for each driver with at least one DWI offense (that is, an administrative sanction and/or court conviction) on his/her driver history record. In addition to demographic characteristics, the data record for each driver included a complete history of impaired driving incidents and other types of traffic violations for all years. Identifying driver information such as name and address was not provided. By linking data elements for historical and current violations on each driver’s data record, it was determined whether a given DWI offense was the first offense, second offense, etc. Effective January 1, 1998, the alcohol test result at the time of arrest is placed on the driver record, and this information was provided for DWI offenses occurring after this date. Prior to 1998, available information on alcohol test results was limited to whether the offender refused or submitted to the test.

It is important to note that the analyses below do not include persons who were arrested for DWI but did not receive either a court conviction or an implied consent driver license revocation. It is estimated that 1 to 2 percent of persons arrested for DWI have no entry on their driver license record due to the rescission of the implied consent revocation, or failure of the officer to invoke implied consent upon arrest, coupled with acquittal, plea bargaining, or dropping of the charge (Cleary, Shapiro, 2001).

In the following analyses of the characteristics and dispositions of DWI cases, statistical differences were examined with the chi-square statistic (p < .05).

Profile of DWI Cases

Profiles of first-time and repeat DWI offenses for the years 1998-2000 were developed, based on the alcohol test result and driver’s age and gender. During the study period, there were differences in the definition of a repeat offense among different sanctions and over time. To provide a consistent basis for comparison, the repeat offenders were defined as those with a prior DWI offense (administrative action and/or court conviction) within the past five years, or two or more offenses (administrative action and/or court conviction) in the past 10 years.

The number of DWI offenses totaled 32,625 in 1997, the year prior to the high-BAC law; 33,662 in 1998; 35,832 in 1999; and 35,737 in 2000. In all four years, about 29 percent were repeat offenses. Also in all four years, female drivers committed about 20 percent of first-time offenses and 14 percent of repeat offenses. The percentage of drivers ages 21-24 increased gradually from 1997 to 2000, rising from 17 percent to 20 percent for first-time offenses and from 14 percent to 17 percent for repeat offenses. A corresponding decline occurred in the percentage of drivers ages 25-34 (32 percent to 28 percent for first-time offenses and 40 percent to 36 percent for repeat offenses). In all four years, drivers under 21 years of age represented about a tenth of first-time offenders and 4 percent of repeat offenders.