Colorado DUI law prohibits driving with a BAC (blood alcohol concentration) of 0.08% or higher, no matter if you feel sober and are being safe. Even if your BAC is lower than 0.08%, you can still be convicted of a drunk driving crime depending on the case.
This chart illustrates Colorado’s drunk driving offenses and their associated unlawful BAC levels.
| Colorado Crime | Illegal BAC |
| DUI per se | 0.08% and higher* |
| DWAI (driving with ability impaired) | Above 0.05% to less than 0.08% |
| Commercial DUI | 0.04% and higher |
| UDD (underage drinking and driving), also called “Baby DUI” or the “Zero Tolerance” policy | 0.02% and higher |
| *Enhanced Penalties: If your BAC is 0.15% or higher, you are designated as a persistent drunk driver and sentenced as a repeat offender. If your BAC is 0.20% or higher, then your minimum jail sentence will be 10 days rather than five. | |
There are different BAC limits for DUI, DWAI, and UDD in Colorado.
What is the BAC limit for DUI in Colorado?
Driving with a BAC of 0.08% or higher is automatically illegal. Even if you are being safe and do not feel any impairment, Colorado prosecutors can bring DUI per se charges against you for driving with a BAC of 0.08% or higher.
Note that you can still face DUI charges even if your blood alcohol content is lower than 0.08%. The state would then have to prove that you were substantially incapable of operating a motor vehicle in a safe manner. The state would rely on such evidence as
- eyewitness testimony,
- video footage, and
- the results of the field sobriety tests (such as the walk-and-turn test).
A first-time DUI with no substantial injuries is a misdemeanor in Colorado. The following table spells out the penalties.
| DUI-1st Penalties in Colorado | |
| Jail | 5 days to 1 year |
| Probation | Up to 2 years |
| Fines | $600 to $1,000 |
| License revocation | 9 months (though it may be possible to get a restricted license if you install an ignition interlock device) |
| Public service | 48 to 96 hours |
| Classes | Possibly Level II Education alcohol classes |
| DMV points | 12 |
Note that if you have a blood alcohol level of 0.15% or higher, you are designated a persistent drunk driver (PDD) and sentenced as a repeat-DUI offender. Then if your BAC was 0.20% or higher, the minimum jail sentence is 10 days, not five.1
What is the BAC limit for DWAI in Colorado?
Driving with a BAC of greater than 0.05% to less than 0.08% is DWAI – driving with ability impaired. You can be convicted of DWAI even if you feel sober and are being safe. Colorado prosecutors just need to prove that your driving was affected by “the slightest degree” by
- alcohol and/or
- drugs.
A first-time DWAI is a misdemeanor in Colorado.2 The following table spells out the penalties:
| DWAI-1st Penalties in Colorado | |
| Jail | 2 to 180 days |
| Probation | Up to 2 years |
| Fines | $200 to $500 |
| License revocation | None |
| Public service | 24 to 48 hours |
| DMV points | 8 |
What is the BAC limit for UDD in Colorado?
Driving while under 21 years old and with a BAC of 0.02% to 0.05% is UDD – underage drinking and driving. This is a very low threshold, and drinking just a small amount of alcohol could cause your BAC to reach 0.02%.
The state does not have to prove a UDD defendant was impaired in any way. Merely crossing the BAC legal limit makes you guilty of UDD. Also called a “baby DUI,” UDDs are part of Colorado’s “zero tolerance” policy for minor drunk driving.
A first-time UDD is a class A traffic infraction. The following table spells out the penalties.
| UDD-1st Penalties in Colorado | |
| Fines | Up to $150 |
| License suspension | Up to 3 months |
| Public service | Up to 24 hours |
| DMV points | 4 |
If you are underage and arrested with a BAC of 0.08% or higher, you face regular DUI charges. Meanwhile, if you are underage and arrested with a BAC of 0.05% to less than 0.08%, you face regular DWAI charges.3
Many factors could cause an inaccurate BAC result, such as contaminated blood samples.
What is the BAC limit for commercial drivers in Colorado?
Driving a commercial vehicle with a BAC of 0.04% or higher is “Excess BAC CDL.” Even if you do not get charged with DUI, the Colorado DMV will suspend your CDL for one year.
Note that if you were transporting hazardous materials at the time, the revocation is extended to three years. Then if you ever get caught again for Excess BAC CDL – or pick up a DUI – then your CDL gets revoked permanently.
Commercial drivers who are under 21 years old are held to a higher standard: Driving a commercial vehicle with a BAC of 0.02% to less than 0.04% is “Excess BAC underage CDL.” The following table spells out the CDL revocation penalties:4
| Excess BAC Underage CDL in Colorado | CDL Revocation Period |
| First offense | 3 months |
| Second offense | 6 months |
| Third or subsequent offense | 1 year |
How do I challenge my BAC results?
Ten common ways to contest BAC results in an alcohol-related driving case are:
- The breathalyzer was not calibrated correctly;
- The technician who maintained the breathalyzer let their certification lapse;
- The police officer did not administer the chemical test within two hours of your driving;
- The police failed to observe you for 15 minutes before taking the chemical breath test;
- The blood test samples were contaminated;
- The blood tests were mixed up with another defendant’s blood tests;
- You suffered from GERD, acid reflux, or auto-brewery syndrome – which may cause an elevated BAC;
- You had dental work that caused any alcohol to pool and return an elevated BAC result;
- You had just taken a medication or mouthwash that contained alcohol; and/or
- The high BAC result was due to rising blood alcohol.
Additional Resources
For more information about Colorado DUI laws, see our related articles:
- I got a DUI in Colorado. How does the court process work? – A detailed guide about criminal and administrative DUI procedures
- 20 ways to beat a Colorado DUI or DWAI – An overview of the most common ways to fight back against drunk driving allegations
- What’s the difference between DUI and DWAI in Colorado? – A comparison and contrast of the state’s two primary drunk driving crimes
Also check out NO DUI Colorado, a Colorado government website with the aim of informing the public about drunk driving laws and post-arrest procedures.
Legal References
- Colorado Revised Statute 42-4-1301; CRS 42-4-1307; CRS 42-2-125; CRS 42-2-125; CRS 42-2-126; CRS 42-2-127; see also Martinez v. People, (2020) CO 3, 455 P.3d; see also Edwards v. Colo. Dept. of Rev., (COA 2016) 406 P.3d 347. SB21-055.
- Same.
- Same.
- CRS 42-2-126; 49 CFR 383.51.