Colorado DUI laws set the BAC limit at 0.08% for adult drivers under Colorado Revised Statutes Section 42-4-1301. A lower charge called DWAI applies at 0.05% to 0.079% BAC. A first DUI offense may bring 5 days to 1 year in jail and a fine of $600 to $1,000. This article covers penalty tiers, marijuana impairment rules, license consequences, and the 2027 ignition interlock change. Facts come from the Colorado Office of Legislative Legal Services and the Colorado General Assembly.
Key Terms Defined
Colorado law separates impaired driving into several distinct charges rather than one single DUI offense. DUI means driving under the influence to a degree that makes a person substantially incapable of driving safely. DWAI means driving while ability is impaired to even a slight degree by alcohol or drugs. DUI per se applies when a chemical test result alone shows 0.08% BAC or higher, regardless of how the driver appeared to behave. UDD applies to underage drinking and driving cases.
DUI, DUI Per Se, DWAI, DUID, and UDD Explained
DUID refers to driving under the influence of drugs, including marijuana, and is prosecuted under the same general DUI framework in Code Section 42-4-1301. UDD applies to drivers under 21 with a BAC between 0.02% and 0.05%, a much lower threshold than the adult standard. These categories often confuse readers because DUI per se needs no observed impairment, while standard DUI can rely on an officer’s observations even below 0.08%. Knowing which category applies changes the penalty range a person may face.
What the Law Says
Colorado Revised Statutes Section 42-4-1301 defines the BAC thresholds that separate DUI, DUI per se, and DWAI charges for drivers over 21. The 0.08% mark triggers DUI per se automatically once a valid chemical test confirms it. A BAC between 0.05% and 0.079% supports a DWAI charge instead, which carries lower penalties at every offense tier. The Colorado Office of Legislative Legal Services DUI and DWAI law summary lists these thresholds alongside the full penalty structure for each offense level.
Blood Alcohol Content Thresholds
A BAC of 0.08% or higher supports DUI per se with no additional proof of impairment required beyond the test result. A BAC from 0.05% up to 0.079% falls into DWAI territory, a lesser charge under Code Section 42-4-1301. Standard DUI can still apply below 0.08% if evidence shows substantial impairment from alcohol or drugs. Drivers under 21 face a separate UDD threshold starting at just 0.02% BAC, reflecting Colorado’s stricter approach to underage drivers.
Marijuana and the Permissible Inference Standard
Marijuana impairment works differently from alcohol under Colorado law. A THC level of 5 ng/mL or more allows a jury to infer impairment, but this permissible inference is not an automatic violation like the 0.08% alcohol threshold. Prosecutors must still prove the driver was actually impaired, even with a THC reading above 5 ng/mL. The Colorado Department of Transportation drugged driving FAQs confirm this distinction, which differs meaningfully from the strict per se alcohol standard.
This permissible inference standard is widely misunderstood and often described inaccurately as a hard legal limit identical to alcohol’s threshold. Colorado’s own guidance clarifies that a THC test result is only one piece of evidence a jury may weigh. The Colorado cannabis driving and traveling rules page reinforces that impairment, not the number alone, remains the legal question. A medical marijuana card does not shield a driver from prosecution if impairment is proven.
Who It Applies To
Colorado DUI and DWAI laws apply to any person operating a motor vehicle on a Colorado road, with different BAC thresholds based on age. Adult drivers age 21 and older face the standard 0.08% DUI per se threshold and the 0.05% DWAI threshold described above. These rules apply uniformly across the state regardless of county, since DUI law in Colorado is governed at the state level rather than by local ordinance.
Adult Drivers
Drivers age 21 and older are subject to the standard thresholds under Code Section 42-4-1301. A BAC of 0.08% or more supports DUI per se, while 0.05% to 0.079% supports DWAI. Below 0.05%, a DUI charge can still apply if evidence shows the driver was substantially incapable of safe driving. There is no separate BAC carve out for adult drivers based on vehicle type under the state statute discussed in this report.
Drivers Under 21
Drivers under 21 face the UDD standard, which applies at a BAC between 0.02% and 0.05%. This threshold is far lower than the adult DWAI level and reflects a zero tolerance approach common among states for underage drivers. A driver under 21 with a BAC of 0.08% or higher still faces the standard adult DUI per se charge rather than UDD. UDD exists specifically to address underage drinking levels below the adult impairment thresholds.
Requirements or Elements
Colorado’s express consent law means that driving on a Colorado road is treated as prior agreement to a chemical test if an officer has reasonable grounds to suspect impaired driving. This rule is separate from the criminal DUI charge itself and carries its own administrative consequences under Code Section 42-2-126. Refusing a test can trigger license revocation independent of whether the driver is later convicted of DUI or DWAI in criminal court.
Express Consent and Chemical Testing
Refusing a chemical test under Colorado’s express consent law can lead to license revocation through a separate administrative process. This administrative action does not require a criminal DUI conviction to take effect. A driver typically has a limited window to request a DMV hearing after an arrest to contest the administrative license action. The express consent framework under Code Section 42-2-126 exists alongside, not instead of, the criminal penalties described in the next section.
Penalties or Consequences
Colorado law sets penalty ranges that increase with each subsequent DUI or DWAI offense within a set look back period. A first DUI offense may bring 5 days to 1 year in jail, a fine of $600 to $1,000, and a 9 month license revocation. DWAI penalties are generally lower than DUI penalties at each offense tier. These ranges come from the penalty tables in the Colorado Office of Legislative Legal Services law summary and Code Section 42-4-1307.
First Offense Penalties
A first DUI conviction may result in 5 days to 1 year in jail under Code Section 42-4-1307, along with a fine between $600 and $1,000. License revocation for a first DUI typically runs 9 months. Colorado law allows the mandatory minimum jail term to be suspended if the offender completes an alcohol or drug evaluation and treatment program, so the mandatory minimum does not always mean actual jail time. A first DWAI conviction carries lower jail and fine ranges than DUI under the same statute.
Second and Third Offense Penalties
Penalties increase for a second or third DUI or DWAI offense under Code Section 42-4-1307, reflecting Colorado’s escalating approach to repeat impaired driving. A driver convicted of a third DUI or DWAI within seven years may also face classification as a Habitual Traffic Offender under Code Section 42-2-202. That classification triggers a mandatory five year license revocation separate from the criminal sentence. Persistent Drunk Driver status can also apply based on high BAC readings, prior offenses, or test refusal history.
Felony DUI (Fourth Offense and Aggravating Factors)
A fourth DUI or DWAI offense in Colorado can be charged as a felony rather than a misdemeanor. Felony DUI carries substantially higher stakes than misdemeanor charges, including longer potential incarceration. Vehicular assault under Code Section 18-3-205 and vehicular homicide under Code Section 18-3-106 can apply when a DUI or DWAI results in serious injury or death, and both carry felony classifications. Anyone facing felony level DUI charges should consult a licensed attorney in your state given the severity of these consequences.
Administrative License Penalties
Separate from criminal court penalties, Colorado’s DMV can revoke a driver’s license through an administrative process tied to BAC results or test refusal under Code Section 42-2-126. A first DUI per se conviction typically triggers a 9 month revocation period administratively. These administrative penalties run alongside, not instead of, any criminal sentence imposed by a court. The point system under Code Section 42-2-125 can also affect a driver’s license status following a conviction.
Exceptions and Limitations
Colorado’s ignition interlock rules are changing under a new law that has not yet taken effect. Current rules under Code Section 42-2-132.5 govern when a restricted license requiring an interlock device becomes available after a revocation. House Bill 26-1242, signed into law May 29, 2026, changes these requirements starting June 1, 2027. Readers should treat current interlock timelines as subject to this confirmed upcoming change.
Ignition Interlock Devices and the 2027 Law Change
An ignition interlock device requires a breath test before a vehicle will start and is often part of a restricted license granted after a DUI related revocation. Current rules are outlined in the Colorado Revised Statutes Section 42-2-132.5 on Justia. The Colorado General Assembly HB26-1242 bill page confirms that starting June 1, 2027, the law eliminates the 2 month waiting period for interlock restricted license eligibility in certain refusal cases.
Starting June 1, 2027, first time DUI, DUI per se, and DWAI offenders will be required to hold an interlock restricted license for the full period of their license revocation rather than a shorter window. This is a confirmed legislative change, not a proposal, since House Bill 26-1242 was signed into law on May 29, 2026. Laws and enforcement may change, so readers should check official state sources for the latest rules before relying on current interlock timelines.
Common Misconceptions
Many people assume the 5 ng/mL THC threshold works exactly like the 0.08% alcohol limit, but Colorado law treats them differently. THC above 5 ng/mL creates a permissible inference of impairment, not an automatic violation, meaning prosecutors must still prove impairment occurred. Another common misconception is that refusing a breath or blood test avoids all consequences, when in fact refusal triggers its own administrative license revocation under the express consent law regardless of the criminal case outcome.
Some readers also assume mandatory minimum jail sentences always mean actual time behind bars. Colorado law allows courts to suspend that mandatory minimum for a first offense when a person completes required alcohol or drug evaluation and treatment programs. Readers should also understand that a Persistent Drunk Driver classification is not a separate criminal charge but a label that increases requirements and penalties tied to an existing DUI or DWAI conviction. For guidance on how this article is intended to be used, see the Disclaimer.
Disclaimer
This article is for general informational purposes only. It is not legal advice. Lawwalls publishes informational content only and does not provide legal services or legal advice.
For legal advice about your specific situation contact a licensed attorney in your state. Laws change and vary by jurisdiction. Verify current rules with official government sources or a qualified lawyer.