How alcohol affects you and the DWI law

Key points

1. Alcohol is involved in more than one third of deaths on Minnesota roads each year.

   Source: Handbook p. 91

   “Alcohol is involved in more than one-third of the deaths on Minnesota roads each year.”
   Minnesota Driver's Manual, Handbook p. 91

2. Your driving ability becomes impaired after just one drink.

   Source: Handbook p. 91

   “Higher alcohol concentration means a greater degree of impairment. Your driving ability becomes impaired after just one drink.”
   Minnesota Driver's Manual, Handbook p. 91

3. A 12 ounce beer, 5 ounce glass of wine, typical mixed drink and 9 ounce wine cooler have about the same alcohol.

   Source: Handbook p. 92

   “A 12-ounce beer, a 5-ounce glass of wine, a typical mixed drink and a 9-ounce wine cooler usually contain about the same amount of alcohol.”
   Minnesota Driver's Manual, Handbook p. 92

4. Coffee, exercise and cold showers do not speed up how fast your body removes alcohol.

   Source: Handbook p. 92

   “Drinking coffee, exercising and taking cold showers do not increase the rate of oxidation.”
   Minnesota Driver's Manual, Handbook p. 92

5. You can be arrested for DWI at 0.08 percent or higher, or 0.04 percent in a commercial vehicle.

   Source: Handbook p. 93

   “A person with an alcohol concentration of 0.08 percent or higher (0.04 percent if driving a commercial vehicle) who is in control of a moving or parked vehicle can be arrested for driving while impaired (DWI).”
   Minnesota Driver's Manual, Handbook p. 93

6. If alcohol caused driving errors, you can be arrested for DWI at as low as 0.04 percent.

   Source: Handbook p. 93

   “the driver can be arrested for DWI with an alcohol concentration as low as 0.04 percent.”
   Minnesota Driver's Manual, Handbook p. 93

7. Under 21, driving with any detectable alcohol is illegal, and a conviction brings a 30 day suspension.

   Source: Handbook p. 95

   “It is illegal for a person under age 21 to operate a motor vehicle with any detectable amount of alcohol in their system. If convicted of this offense, you will have your driving privileges suspended for 30 days.”
   Minnesota Driver's Manual, Handbook p. 95

8. A second underage conviction brings a 180 day suspension.

   Source: Handbook p. 95

   “A second conviction will result in a suspension of driving privileges for 180 days.”
   Minnesota Driver's Manual, Handbook p. 95

9. A commercial driver below 0.04 percent but detectable is put out of service for 24 hours.

   Source: Handbook p. 95

   “If your alcohol concentration is less than 0.04 but detectable, you will be put out of service for 24 hours.”
   Minnesota Driver's Manual, Handbook p. 95

10. Do not drink or keep an open alcohol container inside a vehicle on a public road.

    Source: Handbook p. 96

    “You must not drink or have an open container of any alcoholic beverage inside a motor vehicle when it is on a public street or highway.”
    Minnesota Driver's Manual, Handbook p. 96

Numbers to know

3 questions from the Minnesota practice test

1. 1. At what alcohol concentration can a person controlling a regular moving or parked vehicle be arrested for DWI in Minnesota?

   1. 0.08 percent or higher
   2. 0.04 percent or higher in every case
   3. 0.02 percent or higher
   4. 0.16 percent or higher only
   Show answer

   0.08 percent or higher. For a person in control of a moving or parked vehicle, Minnesota identifies 0.08 percent as the ordinary alcohol-concentration threshold for a DWI arrest. The 0.04 percent figure applies to commercial-vehicle driving, and an officer may also make an arrest at a lower concentration when alcohol-related driving errors can be proved. The 0.16 percent figure signals more severe penalties rather than the basic arrest threshold. Do not treat a parked vehicle as an automatic exception because physical control is included.

2. 2. What alcohol rule applies to a Minnesota driver under age 21 who operates a motor vehicle?

   1. The rule applies only when passengers are present
   2. Only 0.08 percent or more is illegal
   3. Alcohol is allowed if the driver stays below 0.04 percent
   4. Any detectable amount is illegal
   Show answer

   Any detectable amount is illegal. Minnesota's underage rule prohibits operating a motor vehicle with any detectable alcohol in the system. That is stricter than the 0.08 percent threshold often associated with ordinary DWI discussions, and it is not changed by the presence or absence of passengers. The 0.04 percent choice borrows the commercial-vehicle threshold and does not apply here. A second conviction also brings a longer suspension, so the safest operating cue for anyone under 21 is no detectable alcohol before driving.

3. 3. A commercial driver has a detectable alcohol concentration below 0.04 percent. What Minnesota consequence is specified?

   1. The driver receives only a warning with no restriction
   2. The driver may continue after drinking coffee
   3. The driver is placed out of service for 24 hours
   4. The driver permanently loses every driving credential
   Show answer

   The driver is placed out of service for 24 hours. Minnesota places a commercial driver out of service for 24 hours when the alcohol concentration is below 0.04 percent but still detectable. Being below 0.04 does not make detectable alcohol irrelevant, so the warning-only choice is unsafe. Coffee cannot remove the restriction, and the manual's passage describes a 24-hour out-of-service period rather than automatic permanent loss of every credential. The practical cue is commercial vehicle plus any detectable alcohol: stop operating and observe the stated duration.

Source: the Minnesota Driver's Manual, Chapter 8: Driving under the influence of alcohol or drugs. This lesson is a plain English summary, not the law itself; where it differs, the manual and the statute govern. Last checked 2026-09-27.