Drunk and drugged driving laws in Colorado
Colorado has several impaired-driving offenses, not just one. DUI, DUI per se, DWAI and the under-21 offense called UDD each carry their own penalties and license points, and any of them can end a new driver's license quickly.
Cannabis is legal for adults in Colorado, but driving while impaired by it is not. The only safe plan is never to drive after drinking or using drugs.
By the end of this topic you can
- You can name Colorado's impaired-driving offenses and their BAC levels.
- You can explain the tighter limit for drivers under 21.
- You can describe Colorado's express consent law and the cost of refusing a test.
- You can explain how the law treats THC in a driver's blood.
- You can plan a safe ride home.
What you need to know and understand
- A BAC of 0.08 or more at the time of driving, or within two hours after, is DUI per se.
- A BAC over 0.05 but below 0.08 allows a court to infer that your driving ability was impaired (DWAI).
- For drivers under 21, a BAC from 0.02 to 0.05 is the UDD offense, and a BAC over 0.02 but under 0.08 can also lead to a DMV license revocation.
- Five nanograms or more of active THC per milliliter of whole blood allows a court to infer you were under the influence of drugs.
- By driving in Colorado you agree to take a breath or blood test when an officer has probable cause (express consent).
- Refusing a test brings license revocation: one year for a first refusal, longer for repeats.
- License points: DUI or DUI per se 12, DWAI 8, UDD 4.
The levels that matter
- Under 21: a BAC of 0.02 to 0.05 is already an offense (UDD); higher levels can bring DWAI or DUI charges.
- Over 0.05 and under 0.08: evidence that you were driving while ability impaired (DWAI).
- 0.08 and above: DUI per se, and evidence of DUI.
- Drugs: any drug, legal or not, that impairs you can lead to DUI or DWAI. For THC, 5 nanograms or more per milliliter of blood supports a finding that you were under the influence.
Express consent and what refusal costs
Colorado's express consent law means that driving on its roads counts as agreeing to be tested if an officer has probable cause to suspect DUI, DUI per se, DWAI or UDD. Adults can generally choose breath or blood. For a suspected UDD offense, a driver under 21 gives a breath test. Once you choose a test you cannot switch, and failing to complete it counts as a refusal.
A refusal leads to revocation of your license for one year on a first violation, two years for a second and three years for a third or later. For adults 21 and over, a first excess-BAC revocation for 0.08 or more is nine months. Criminal penalties from the court come on top of these license actions.
Planning to stay safe
Points are only part of it. A teen with 12 DUI points instantly passes the suspension threshold, and a conviction can follow you for years. Plan ahead: agree a no-questions-asked pickup with a parent, use a ride service, or stay where you are. Never ride with a driver who has been drinking or using cannabis. Our guide to Colorado teen license restrictions and penalties explains how impaired-driving offenses affect young drivers.
Common mistakes
- Believing you are safe under 0.08. Above 0.05 can bring DWAI, and under 21 the limit is 0.02.
- Thinking legal cannabis means legal to drive after using it.
- Assuming you can refuse a test with no consequence; refusal costs at least a year of driving.
- Driving the morning after heavy drinking, when your BAC may still be high.
Test yourself: Drunk and drugged driving laws in Colorado
Answer each question, then read the explanation. Questions come in a random order each time.
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Sources: Colorado Revised Statutes, Title 42 (Colorado General Assembly): sections 42-4-1301, 42-4-1301.1, 42-2-126 and 42-2-127. Independent guide, not affiliated with any licensing agency. Always check the latest official rules with the Colorado licensing agency.