Alcohol and DUI

By the end of this topic you can

• You can state the adult BAC limit and the stricter limits for under-21 and commercial drivers.
• You can explain implied consent and what happens if you refuse a test.
• You can describe how alcohol affects driving skills.
• You can plan a safe way home that does not involve driving after drinking.

What you need to know and understand

• BAC means blood alcohol concentration: how much alcohol is in your blood.
• Every state uses a 0.08 percent BAC limit for drivers 21 and over, except Utah, which uses 0.05.
• Commercial drivers have a 0.04 limit in commercial vehicles.
• The legal drinking age is 21 in every state, set through federal highway funding rules.
• Every state has a zero tolerance law for drivers under 21, with a limit of 0.02 or lower; some states, such as California, use 0.01.
• You can be arrested for DUI below the limit if your driving is impaired.
• Implied consent means that by driving you agree to a chemical test if an officer suspects DUI. Refusing usually brings an automatic license suspension; the length varies by state (one year in California).
• Most states ban open alcohol containers in the passenger area of a vehicle.

How alcohol changes your driving

Alcohol starts to affect you well before you feel drunk. Judgment is usually hit first, which is why people who have been drinking often think they are fine to drive. Then reaction time, coordination, tracking of moving objects and the ability to do two things at once all get worse.

Only time removes alcohol from your body. Coffee, cold showers, food or fresh air do not sober you up. A standard drink is roughly 12 ounces of regular beer, 5 ounces of wine or 1.5 ounces of liquor, and each contains about the same amount of alcohol.

Limits and penalties at a glance

• Drivers 21 and over: 0.08 BAC in all states except Utah (0.05).
• Drivers under 21: zero tolerance, 0.02 or lower depending on the state.
• Commercial drivers in commercial vehicles: 0.04.
• Penalties can include license suspension, fines, jail, an ignition interlock device, DUI school and much higher insurance costs. Details vary by state: check your state manual.
• Under-21 drivers often face extra penalties for simply having alcohol in the car.

Making a safe plan

1. Decide before you go out how you will get home.
2. Choose a sober designated driver, or plan a ride share, taxi or public transport.
3. If you have been drinking, give your keys to someone sober.
4. Never ride with a driver who has been drinking.
5. If you see a driver who seems impaired, keep your distance, pull over safely and call 911.

Common mistakes

• Believing you are fine because you only had a couple of drinks: impairment starts below the limit.
• Thinking coffee or a cold shower will sober you up: only time works.
• Assuming a refusal avoids trouble: refusing a test usually brings its own suspension.
• Keeping an opened bottle in the passenger area: open containers are banned in most states.
• Forgetting that under-21 limits are almost zero: any drinking can mean a DUI.

Test yourself: Alcohol and DUI

Answer each question, then read the explanation. Questions come in a random order each time.

Go deeper

• Implied Consent Law and DUI in the US
• Zero Tolerance Laws for US Drivers Under 21
• How Alcohol Affects Driving