Impaired Driving: Alcohol, Cannabis & Medications

Alcohol-impaired crashes kill thousands of people in the U.S. every year, about one-third of all traffic deaths. Cannabis, many prescription drugs and even some over-the-counter medicines also slow reactions and judgment. Impaired driving is completely preventable.

• All drivers
• Teen drivers
• Utah

Alcohol

• The legal limit is 0.08% blood alcohol in every state except Utah, where it’s 0.05%.
• Drivers under 21 face zero-tolerance laws: any measurable amount can be illegal.
• Commercial drivers have a limit of 0.04% in a commercial vehicle, and a DUI in their own car can cost them their CDL. See DOT Drug & Alcohol Testing.
• Impairment starts well below the legal limit. Even one or two drinks reduce your ability to track moving objects and react.

Only time sobers you up. Coffee, cold showers and food don’t lower blood alcohol. Your body clears roughly one standard drink per hour.

Cannabis

• Cannabis slows reaction time, affects attention and coordination, and makes it harder to stay in your lane.
• Driving high is illegal in every state, even where cannabis is legal.
• Effects from edibles can be delayed and last for hours.
• Combining cannabis and alcohol is worse than either alone.

Medications

• Many medicines can impair driving: some pain relievers, sleep aids, anxiety medicines, muscle relaxants, antihistamines and cold medicines.
• Read warning labels for “may cause drowsiness” or “use care when operating a vehicle.”
• Ask your pharmacist or doctor how a new medicine might affect your driving, and don’t drive until you know how it affects you.
• Driving impaired by a legal prescription can still be a DUI.

Plan ahead

• Pick a sober designated driver before the event.
• Use a rideshare, taxi or transit, or stay the night.
• Take the keys from a friend who’s been drinking.
• If you see a driver who seems impaired, keep your distance and call 911 when safe.

Consequences

A DUI can mean arrest, jail, license suspension, an ignition interlock, huge insurance costs and losing a job that requires driving. A crash can mean killing someone. If alcohol or drugs are a problem for you, help is available. See Overdose & Naloxone and the free SAMHSA helpline at 1-800-662-4357.

Last updated: October 1, 2026