Colorado DUI laws set the legal blood alcohol limit at 0.08% for a standard DUI charge under Colorado Revised Statutes Section 42-4-1301. A lesser charge called DWAI applies when blood alcohol content falls between 0.05% and 0.079%. Drivers under 21 face a zero tolerance limit of 0.02% under the underage drinking and driving rule. This guide covers penalties, license consequences, ignition interlock rules, and implied consent requirements as defined by the Colorado Department of Revenue and the Colorado General Assembly.
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What Counts as DUI in Colorado
Colorado Revised Statutes Section 42-4-1301 defines driving under the influence as operating a vehicle after consuming alcohol or drugs to a degree that leaves a person substantially incapable of exercising clear judgment or safe control. A separate and lesser offense called driving while ability impaired applies when a person is affected to only a slight degree. Both DUI and DWAI are generally charged as misdemeanors under Colorado law, though repeated offenses can raise the severity significantly over time.
A person with a blood alcohol content of 0.08% or higher commits DUI per se, meaning the charge applies automatically regardless of whether visible impairment can be proven. This differs from a standard DUI charge, which still requires evidence that alcohol or drugs affected the driver. Blood alcohol content between 0.05% and 0.079% creates a permissible inference of impairment, which typically supports a DWAI charge rather than DUI per se under Colorado Drunk Driving Laws — Colorado Law Summary (Office of Legislative Legal Services).
Colorado law also addresses marijuana impairment separately from alcohol. If a blood test shows five nanograms or more of delta-9 tetrahydrocannabinol per milliliter, this creates a permissible inference that the driver was under the influence of drugs. This is not an automatic per se limit the way 0.08% is for alcohol. A jury may consider the inference but is not required to conclude impairment from the THC level alone, and prosecutors must still present supporting evidence.
Blood Alcohol Content Thresholds Explained
Colorado uses several distinct blood alcohol content thresholds that trigger different charges and consequences. A reading of 0.08% or above results in DUI per se, the most serious standard alcohol charge under state law. A reading between 0.05% and 0.079% creates a permissible inference of impairment that generally supports a DWAI charge instead. Below 0.05%, a charge can still apply if other evidence of impairment exists.
Drivers under 21 face a much stricter standard. A breath alcohol content of at least 0.02% but not more than 0.05% while driving, or within two hours after driving, qualifies as underage drinking and driving under state law. This zero tolerance policy reflects the fact that any detectable alcohol level can result in an alcohol related charge for someone who is legally too young to drink at all.
A blood alcohol content of 0.15% or higher can result in a person being classified as a persistent drunk driver, even on a first offense. This designation is separate from the underlying DUI or DWAI charge itself and carries its own extended consequences, particularly around ignition interlock requirements described later in this guide. The 0.15% threshold applies regardless of whether the person has any prior alcohol related driving history.
Express Consent and Chemical Testing
Colorado’s Express Consent Law states that any person who drives in the state has already agreed in advance to submit to a chemical test if a law enforcement officer has reasonable grounds to believe the person is driving under the influence or impaired by alcohol or drugs. This consent is automatic and applies the moment a person operates a vehicle on Colorado roads, regardless of whether the driver later objects to testing at the time of arrest.
Acceptable chemical tests include breath, blood, saliva, or urine analysis, though breath and blood testing are the most commonly used methods for confirming blood alcohol content. Neither a roadside preliminary breath test nor a test performed later at a detox facility satisfies this legal testing requirement on its own. Only an evidentiary breath test administered by an officer or a blood test requested by law enforcement fulfills the chemical testing obligation described in Colorado DMV Alcohol DUI page.
Refusing to take, complete, or cooperate with a required chemical test carries significant consequences under Colorado law. For violations occurring on or after January 1, 2014, a refusal results in a one year license revocation for a first offense and automatically triggers a persistent drunk driver designation. This designation requires completion of a Level II alcohol and drug education and treatment program before driving privileges can be restored in full.
Criminal Penalties by Offense Number
A first DWAI conviction is a misdemeanor carrying two to 180 days in jail, a fine of $200 to $500, and 24 to 48 hours of public service under Colorado Revised Statutes Section 42-4-1307. A first DUI or DUI per se conviction carries a harsher range of five days to one year in jail, a fine of $600 to $1,000, and 48 to 96 hours of public service. These ranges give courts discretion while still setting firm statutory limits.
A second DWAI or DUI conviction, when either offense follows one prior DWAI or DUI, carries 10 days to one year in jail and a fine of $600 to $1,500, with 48 to 120 hours of public service required. A third DWAI or DUI conviction following two prior offenses increases the mandatory minimum to 60 days, while the jail range still extends up to one year and the fine range and public service hours remain the same as the second offense tier.
A fourth or subsequent DWAI or DUI offense is charged as a class 4 felony rather than a misdemeanor, carrying two to six years of imprisonment and three years of mandatory parole under state sentencing law. Public service of 48 to 120 hours applies only if the court sentences the offender to probation rather than imprisonment. This felony threshold was created through House Bill 15-1043, which took effect in 2015 and remains the current standard for repeat offenses in Colorado.
Separately, underage drinking and driving carries its own penalty structure tied to blood alcohol content rather than repeat offense history. A first UDD offense is a class A traffic infraction with no jail exposure, carrying a fine of $15 to $100 and up to 24 hours of public service. A second or subsequent UDD offense becomes a class 2 traffic misdemeanor, carrying 10 to 90 days in jail and a fine of $150 to $300.
Administrative License Consequences
Separate from criminal court penalties, the Colorado Department of Revenue imposes administrative license consequences through the Division of Motor Vehicles. A blood alcohol content test result of at least 0.08% while driving results in a nine month license revocation on a first administrative action. A second test result of at least 0.08% raises the revocation period to 12 months, and a third or subsequent result extends it to 24 months under state administrative rules.
Administrative penalties also apply based on conviction rather than test result alone. A first DUI conviction carries a nine month revocation and 12 points assessed against the license. A second DUI or DWAI conviction carries a 12 month revocation, with DWAI convictions assessed 8 points and DUI convictions assessed 12 points. A third DUI or DWAI conviction extends the revocation to 24 months with the same point structure applied by offense type.
These administrative penalties operate independently of criminal court penalties, meaning a person can face both a criminal sentence and a separate license action arising from the same incident. However, administrative penalties for the same incident are not applied consecutively. If a license was already suspended based on a blood alcohol content test result, a later DUI conviction from that same incident does not add a second separate suspension on top of the first one.
Ignition Interlock Requirements
An ignition interlock device requires a driver to provide a breath sample before a vehicle will start and periodically while driving, preventing operation if elevated alcohol is detected. Colorado requires interlock installation in a range of situations tied to DUI arrests, chemical test refusals, and persistent drunk driver designations, with the specific timing and duration depending on when the arrest occurred relative to January 1, 2023.
For arrests occurring before January 1, 2023, a first per se or DUI conviction allowed early reinstatement after serving one month of revocation, with a two year interlock requirement for blood alcohol content above 0.15% or an eight month requirement for a lower reading. A second or subsequent per se conviction under the older rules required a full two year interlock period, also available after one month of served revocation according to Colorado DMV Ignition Interlock Program.
For arrests occurring on or after January 1, 2023, the timing changed so that early reinstatement can begin on the first day the revocation action goes active rather than after a waiting period. A first per se or DUI conviction now carries a two year interlock requirement for blood alcohol content above 0.15%, or a nine month interlock requirement running concurrently with a nine month revocation period for readings below 0.149%. A second or subsequent per se conviction still carries a two year interlock requirement.
Refusing a chemical test triggers an automatic two year interlock requirement regardless of prior history, though early reinstatement may be available after serving two months of revocation on a first, second, or third or later refusal offense. Any interlock restricted driver who operates a non-equipped vehicle or attempts to bypass the device faces a further license revocation of at least one year with no driving permitted during that period.
Persistent Drunk Driver Designation
A person may be classified as a persistent drunk driver under several distinct circumstances rather than a single fixed rule. This designation applies to a person with a blood alcohol content of 0.15% or more on a single offense, a person convicted of or revoked for two or more prior alcohol related driving violations, a person who continues driving after a license restraint has already been imposed, or a person who refuses required chemical testing.
The persistent drunk driver designation is separate from the underlying criminal charge and functions primarily to extend ignition interlock and treatment requirements rather than to create a new criminal offense on its own. A person designated as a persistent drunk driver must complete a Level II alcohol and drug education and treatment program and generally must maintain an interlock restricted license for a minimum of two years upon reinstatement of driving privileges.
Habitual Traffic Offender Rule
Colorado Revised Statutes Section 42-2-202 establishes a separate escalation path known as the habitual traffic offender rule, which applies when a person is convicted of three qualifying offenses within a seven year period measured from the date of violation rather than the date of conviction. Qualifying offenses include driving under suspension or revocation, DWAI, DUI, reckless driving, vehicular assault, and vehicular homicide.
A person meeting the habitual traffic offender threshold faces a mandatory five year license revocation, which applies in addition to and separately from the felony DUI classification that applies specifically to a fourth or subsequent DUI or DWAI conviction. These two escalation tracks use different counting periods and different triggering offenses, so a person can potentially face one without the other depending on the specific offenses and timing involved.
Vehicular Assault and Vehicular Homicide
When alcohol or drugs are involved in a crash causing serious bodily injury, Colorado charges the offense as vehicular assault rather than a standard DUI or DWAI. Vehicular assault while driving under the influence is a class 4 felony, while vehicular assault while driving while ability impaired is a class 5 felony under Colorado Revised Statutes Section 18-3-205, reflecting a more serious classification than a standard repeat offense misdemeanor.
When a crash involving alcohol or drugs causes death, Colorado charges the offense as vehicular homicide under Colorado Revised Statutes Section 18-3-106. Vehicular homicide while driving under the influence is a class 3 felony, while vehicular homicide while driving while ability impaired is a class 4 felony. General felony sentencing ranges for these offenses are set separately under Colorado Revised Statutes Section 18-1.3-401 and can apply even to a first time offender with no prior driving record.
Additional Fees and Financial Costs
Beyond the base statutory fine range tied to each offense, a person convicted under Colorado DUI laws typically faces court costs assessed by the presiding court in addition to the fine itself. State law also allows a penalty surcharge of up to $500 that helps fund treatment and monitoring programs aimed at persistent drunk drivers specifically, separate from the general fine amount imposed for the underlying conviction.
Additional surcharges may apply to benefit the crime victim compensation fund, along with separate fees required to reinstate a license following a suspension or revocation period. A person sentenced to probation following a third or subsequent offense, or any felony DUI or DWAI conviction, must also submit to at least 90 days of continuous alcohol monitoring unless a court finds monitoring would not serve the interest of justice.
Common Misconceptions About Colorado DUI Law
A common misconception treats the marijuana THC threshold the same way as the 0.08% alcohol limit, assuming that five nanograms per milliliter automatically proves impairment. In reality, Colorado law describes this figure only as a permissible inference, meaning a jury may consider it as one piece of evidence but is not required to find impairment based on the THC level alone, unlike the automatic nature of DUI per se for alcohol.
Another common misconception assumes DWAI is a minor citation rather than a real criminal charge. Under Colorado Revised Statutes Section 42-4-1307, a first DWAI conviction is still a misdemeanor carrying jail exposure, a fine, and mandatory public service hours, even though the blood alcohol content threshold for DWAI sits below the 0.08% level required for DUI per se. Colorado law generally treats both offenses as part of the same overall enforcement framework rather than treating DWAI as informal or non-criminal.
Laws and enforcement may change. Because Colorado has adjusted ignition interlock timing rules and felony DUI thresholds in past years, readers should check official state sources for the latest rules described in Colorado General Assembly DUI/DWAI legislative summary rather than relying solely on older secondary summaries. The administrative process for license consequences is handled separately from the criminal court process described in Colorado DMV The DUI Process, and both processes can affect a person following a single incident. See the Disclaimer below for further information about how this guide is intended to be used.
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.