According to the American Association of Motor Vehicle Administrators (AAMVA), a Michigan study shows repeat offender laws are working. In a study conducted by the University of Michigan Transportation Research Institute (UMTRI) on Michigan's repeat offender laws shows that the number of crashes involving repeat offenders with multiple alcohol convictions has decreased 39 percent since the laws were enacted.

According to AAMVA, the study also found that the crash rate for drivers under suspension or revocation decreased 30 percent, resulting in a 37 percent decrease in injury rates and a 13 percent decrease in fatalities. The number of drivers with two or more alcohol-related convictions dropped 5 percent, while the number of drivers with three or more alcohol-related convictions dropped 18 percent. Under the repeat offender laws, motorists arrested for drunk driving a second time, or driving on a suspended license a third time, will have their metal license plate confiscated. If convicted, their vehicles can be immobilized for up to six months. Drivers whose licenses are revoked for three or more drunk driving or four driving-with-suspended-license convictions cannot register a vehicle until they are relicensed.