Driving Under the Influence of Alcohol or Drugs: Alcohol in a Third of Road Deaths, Drugs and Household Products, How Alcohol Attacks Judgment, Vision, Reaction, Steering, Perception, Coordination and Attention, Standard Drinks and Proof, One Drink Per Hour, Why Coffee Does Not Help, Lower-Risk Choices, the 0.08 and 0.04 Limits and Arrest at 0.04, Implied Consent and Refusal, the Preliminary Breath Test, First, Second and Third Offense Penalties, the Ignition Interlock and 0.02, Felony DWI, the Under-21 No-Tolerance Rule, Commercial Drivers, Cannabis Use and Open Package Laws and the Open Container Rule
Written for aiforu2 as the source for a practice-test bank and the on-device tutor for the Minnesota Class D knowledge test. The facts follow the official manual; the wording is ours.
Source: Minnesota Driver's Manual (DPS DVS, June 2026 edition), Chapter 8 "Driving under the influence of alcohol or drugs" (pages 91–96).
Alcohol, drugs and the toll
Driving impaired by alcohol or any other substance is illegal. Alcohol is involved in more than one-third of Minnesota road deaths, impaired-driver crashes kill about 240 people a year and injure thousands, the person most often killed is the impaired driver, and young men are the likeliest offenders. Impairment by drugs is just as dangerous and just as illegal, whether from illegal drugs, prescriptions, over-the-counter medicines such as cold remedies, or household products, all of which can cause drowsiness; legal drugs that do not impair alone can be powerfully intoxicating with alcohol. A prescribed drug is allowed if the doctor says it will not affect your driving; read warning labels, follow the doctor's orders, avoid illegal drugs, and never use a drug to mask fatigue, whose only cure is rest.
How alcohol affects driving
Alcohol is a depressant; the alcohol concentration in the blood determines the impairment, and driving is impaired after one drink. It attacks judgment (you misjudge your own impairment, speed, stopping distance, belt use and defensive driving), vision (less eye movement and peripheral vision, blurring at high levels), reaction time, steering (over-steering, weaving and running off the road), perception of sights and sounds, coordination and balance, and attention to the many tasks of driving.
Things to know about alcohol
A 12-ounce beer, a 5-ounce glass of wine, a typical mixed drink and a 9-ounce wine cooler hold about the same alcohol, though mixed drinks may exceed the standard 1.5 ounces and beers vary by as much as 40 percent. Proof is twice the alcohol percentage, so 80-proof whiskey is 40 percent alcohol. Drinking more than one standard drink an hour raises your concentration, and effects vary with age, sex, weight, mood, food, metabolism and genetics, and from one occasion to the next; men's greater muscle absorbs alcohol less readily than fat, so a person with more body fat reaches a higher concentration from the same drinks. Only time lowers your concentration, at roughly one drink per hour; the liver oxidizes about 95 percent and the rest leaves by breath, sweat and urine, and coffee, exercise and cold showers change nothing. If you drink, do not drive: designate a sober driver, call a taxi, rideshare, friend or relative, stay over, take an impaired friend's keys, and make the plan while sober.
The DWI law and implied consent
A person with an alcohol concentration of 0.08 percent or higher (0.04 in a commercial vehicle) who is in control of a moving or parked vehicle can be arrested for DWI, and if the officer can prove alcohol caused driving errors, arrest is possible at a concentration as low as 0.04. The law also covers off-road recreational vehicles and motorboats. Under implied consent, an officer with probable cause can require a blood, breath or urine test; refusing is a crime that revokes your privileges for one to six years depending on your record. A roadside preliminary breath test guides the officer and has limited use in court; a test may be demanded when you are under arrest for DWI, refuse or fail the preliminary test, or are in an alcohol-related crash with injury, damage or death. The preliminary test can also help a sober driver who appears impaired because of a medical condition, and officers will get medical help for ill drivers.
Penalties
An alcohol-related revocation brings a $680 reinstatement fee, a new license application and possibly the Ignition Interlock program, plus criminal penalties that grow with prior arrests, a concentration of 0.16 or more, a child under 16 in the vehicle, being under 21, or refusing the preliminary test. At 0.08 or more, or on refusal, you may get a seven-day temporary license and then a revocation. First offense: at least a 90-day revocation (30 days if you plead guilty), no work permit for the first 15 days and until reinstatement requirements are met (none at all at 0.16 or above), optional interlock enrollment, and up to 90 days in jail and/or a $1,000 fine. Second offense within ten years: at least a one-year revocation, possible required interlock, up to one year in jail and/or $3,000, and impounded plates. Third offense within ten years: at least three years without a license, cancellation, a chemical use assessment, required interlock, up to a year in jail and/or $3,000, a forfeited vehicle and impounded plates, and jail or maximum bail with electronic monitoring. The ignition interlock connects to the starter and blocks starting at a concentration of 0.02 or more; first offenders at 0.16 or above may regain privileges through the program, and drivers canceled as "inimical to public safety" must enroll for three to six years. A fourth DWI in ten years, a prior felony DWI or criminal vehicular homicide while impaired is felony DWI, costing the license for four years plus rehabilitation, with up to seven years in prison, five years of conditional release and a $14,000 fine.
Under 21, commercial drivers and cannabis
The drinking age is 21, and a driver under 21 with any detectable alcohol loses the privilege for 30 days, and 180 days for a second conviction. A commercial license is lost for at least one year for driving a commercial vehicle at 0.04 or more (below 0.04 but detectable means 24 hours out of service), driving any vehicle at 0.08 or more, refusing a test, being under the influence of a controlled substance, leaving a crash scene or using any vehicle in a felony; three years if in a hazardous-materials vehicle; permanent loss for a second offense or for a controlled-substance felony in a commercial vehicle; and no commercial work permit during a withdrawal after an impaired arrest in a passenger vehicle. It is illegal to drive under the influence of any cannabis product, hemp edible or artificial cannabinoid, to use such products in a vehicle on a road, or to possess them in a private vehicle with the package opened, the seal broken or contents removed, unless kept in the trunk or, without a trunk, in an area not normally occupied by driver or passengers, never the glove box or utility compartment; an absent owner who allows it is liable too. No one may drink or keep an open container of alcohol in a vehicle on a public road, the driver may not allow a passenger to, and controlled substances may not be used, possessed or sold in a vehicle.
Practise this with Minnesota Driver License questions
More of this guide
Who needs a Minnesota license and the 60-day rule, identification, Driver's License for All, REAL ID and enhanced cards, the written test, the 20/40 and 105-degree vision standards, the road test and its instant failures, the instruction permit and provisional license with their night and passenger limits, Vanessa's Law, the under-21 license, farm, medical and moped licenses at 15, license classes and renewal.
Required equipment and headlight rules, tire pressure and the penny test, window tint, the basic speed law and default limits, the 10 mph passing allowance, signaling 100 feet, blind spots, left and right turns, turning on red, roundabouts, J-turns, divided highways, U-turns, right-lane travel, passing rules and the 700-foot sight line, backing, and every parking rule.
Who must buckle up and the exemptions, rear-facing until two and boosters to nine, children under 13 in back, unattended children and pets, airbags, littering, duties after a crash and the 72-hour rule, no-fault insurance and its penalties, registering within 60 days, the texting ban, and suspension, revocation, limited licenses and cancellation.
Where you must come to a complete stop, school bus yellow lights at 100 and 300 feet, stopping 20 feet from red lights and the $500 penalty, safety patrols and crossing guards, who yields at intersections, transit buses, funeral processions, pulling over for sirens, the Move Over law, careless and reckless driving, how to behave when police stop you, fleeing penalties and pedestrian rules.
Bike lanes, the three-foot pass across the center line, bicycle laws and hand signals, mopeds, following and crowding motorcycles, lane splitting at 25 mph and lane filtering, vulnerable road users, neighborhood electric vehicles, passing and following trucks, the No Zones, crossing devices and the 10-foot rule, second trains, the ENS sign, work zone fines and the zipper merge.
Sign colors and shapes, regulatory signs from Stop to Center Lane Left-Turn Only, warning signs including railroad, school, slow-moving vehicle and intersection signs, construction signs and the $300 fine, route markers, every signal light and arrow, gridlock, pedestrian signals, lane-use control signals, ramp meters, white and yellow lines, turn, center, reversible and carpool lanes and traffic officers.
Scan, Identify, Predict, Decide and Execute, the three-second rule, stopping distance, low beams within 1,000 and 200 feet, entering and leaving the freeway, ramp meters, buses on the shoulder, the diverging diamond, stopping on a freeway, distraction types and illegal behaviors, aggressive drivers, projecting loads, towing rules and limits, winter driving, snowplows, the survival kit and being stranded.
Staying alert every 100 miles or two hours, handling a skid, anti-lock brakes, rain and fog, hydroplaning at 35 mph, never coasting downhill, blowouts, steering and brake failure, running off the pavement, deer from dusk to dawn, a vehicle in your lane, stalling on the tracks, flooded roads, plunging under water, fire, overheating, a stuck gas pedal, utility poles and carbon monoxide.