DUI Defense in Denver

If you were arrested for DUI in Colorado, you are likely dealing with two immediate realities: a criminal case and a ticking clock on your driver’s license. The decisions you make in the next few days will shape both outcomes. Colorado’s DUI laws impose mandatory penalties even for first offenses, and the administrative process that can revoke your license operates on a separate, faster timeline than the criminal case. Understanding what you are facing—and what can be challenged—is the first step toward protecting your future.

At Masterson Hall, Jolie Masterson and Jesse Hall defend clients charged with every type of impaired driving offense in Colorado. This page explains the law, the penalties, and the defense strategies that can make a difference.

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Colorado DUI Law: What You Need to Know

Colorado’s impaired driving laws are found primarily in C.R.S. § 42-4-1301 and carry distinct charges depending on the substance involved and the driver’s level of impairment.

DUI (Driving Under the Influence) — C.R.S. § 42-4-1301(1)(a)

A person commits DUI when they operate a motor vehicle while substantially incapable—because of alcohol, drugs, or both—of exercising clear judgment, sufficient physical control, or due care in the safe operation of a vehicle. If a chemical test shows a blood alcohol concentration (BAC) of 0.08% or higher, there is a presumption that the driver was under the influence.

DWAI (Driving While Ability Impaired) — C.R.S. § 42-4-1301(1)(b)

DWAI is a lesser offense. It applies when a driver has consumed alcohol or drugs to a degree that affects them to the slightest degree, rendering them less able than they ordinarily would be to exercise clear judgment, sufficient physical control, or due care. A BAC between 0.05% and 0.08% creates a presumption of impairment. DWAI carries lighter penalties than DUI, but it is still a criminal offense with lasting consequences.

DUI Per Se — C.R.S. § 42-4-1301(2)(a)

DUI per se means driving with a BAC at or above 0.08%, regardless of whether the driver appeared impaired. The chemical test result alone establishes the offense. This charge often accompanies a standard DUI charge, giving prosecutors two theories to prove.

DUID (Driving Under the Influence of Drugs) — C.R.S. § 42-4-1301(1)(c)

Colorado treats drug-impaired driving the same as alcohol-impaired driving. A person commits DUID when they operate a motor vehicle while under the influence of any drug or combination of drugs that renders them substantially incapable of safe driving. For THC (the active compound in marijuana), a blood level of 5 nanograms per milliliter or higher gives rise to a permissible inference of impairment—but unlike alcohol, there is no “per se” threshold. Prosecution must still prove actual impairment. Notably, having a valid medical marijuana card is not a defense under the statute.

Colorado’s Express Consent Law — C.R.S. § 42-4-1301.1

Under Colorado’s express consent law, anyone who drives on Colorado roads is deemed to have consented to a chemical test of their blood or breath if an officer has probable cause to believe they are driving under the influence. While you may decline the voluntary roadside breath test before arrest (unless you are under 21), refusing the evidentiary chemical test after arrest triggers automatic consequences: a one-year license revocation for a first refusal, a mandatory two-year ignition interlock requirement upon reinstatement, and possible designation as a Persistent Drunk Driver. The refusal itself is also admissible as evidence at trial.

Penalties — C.R.S. § 42-4-1307

Colorado’s sentencing structure for impaired driving offenses is found in C.R.S. § 42-4-1307 and escalates significantly with each subsequent conviction. The state counts all prior DUI, DUI per se, and DWAI convictions regardless of when they occurred—there is no lookback period.

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Types of Charges We Defend

Masterson Hall handles every category of impaired driving charge in Colorado. Each type involves different legal standards, different evidence, and often different defense strategies.

DUI and DUI Per Se

Standard DUI charges are the most common impaired driving cases in Colorado. Whether the prosecution relies on the officer’s observations of impaired behavior or a BAC test result at or above 0.08%, the defense often centers on the quality of the evidence: Was the traffic stop lawful? Were the field sobriety tests administered correctly? Was the chemical test accurate and properly handled?

DWAI

A DWAI charge means the state believes your ability was impaired “to the slightest degree.” While this is a lesser offense than DUI, it still results in a criminal conviction, points on your driving record, and potential jail time. Prosecutors sometimes offer DWAI as a plea reduction from DUI, but accepting that deal is not always in your best interest—particularly when the underlying evidence is weak.

DUID (Drugged Driving)

Colorado’s legalization of marijuana has not changed the DUI statute. Driving under the influence of marijuana, prescription medications, or any controlled substance is prosecuted under the same statute as alcohol-related DUI. DUID cases present unique challenges for both sides: drug recognition evaluations are subjective, blood test timing can affect THC levels significantly, and the 5 ng/mL permissible inference threshold is a presumption—not proof—of impairment. Many people who use marijuana regularly may test above this level without being impaired.

Felony DUI (Fourth or Subsequent Offense)

Since 2015, a fourth DUI, DUI per se, or DWAI conviction in Colorado is classified as a class 4 felony under C.R.S. § 42-4-1301(1)(a)(I), carrying two to six years in the Colorado Department of Corrections, a mandatory three-year parole period, and fines of at least $2,000. If a court imposes probation instead of prison, it must still order a minimum of 90 to 180 days in jail. The stakes in a felony DUI case are categorically different from a misdemeanor—this is a charge that can result in years in state prison.

DMV Administrative Hearings

A DUI arrest in Colorado triggers two parallel proceedings. The criminal case moves through county or district court. Simultaneously, the Colorado Department of Revenue initiates an administrative process to revoke your driver’s license. You have only seven days from the date of your arrest (or from receipt of blood test results) to request an administrative hearing—miss this deadline and your license is automatically revoked. The administrative hearing is a separate proceeding with different rules, different burdens of proof, and different possible outcomes than the criminal case. Both must be defended.

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Penalties and Sentencing

Colorado’s DUI penalties escalate with each offense and increase further when aggravating factors—such as a high BAC, an accident, or a child in the vehicle—are present.

First Offense DUI

• Jail: 5 days to 1 year (mandatory jail if BAC is 0.20% or higher)
• Fines: $600 to $1,000 plus court costs and surcharges
• Community service: 48 to 96 hours
• License revocation: 9 months
• Ignition interlock device (IID): 8 months minimum; 2 years if BAC was 0.15% or higher
• DMV points: 12
• Alcohol/drug evaluation and treatment: Required

First Offense DWAI

• Jail: 2 to 180 days
• Fines: Up to $500 plus court costs
• Community service: 24 to 48 hours
• License: No automatic revocation for a first DWAI (8 DMV points)
• Alcohol/drug evaluation and treatment: Required

Second Offense DUI

• Jail: 10 days to 1 year (mandatory 10-day minimum)
• Fines: $600 to $1,500 plus court costs
• Community service: 48 to 120 hours
• License revocation: 1 year
• IID: 2 years minimum
• Probation: Mandatory minimum 2 years
• Persistent Drunk Driver designation: Likely, requiring Level II alcohol education

Third Offense DUI

• Jail: 60 days to 1 year (mandatory 60-day minimum)
• Fines: $600 to $1,500 plus court costs
• Community service: 48 to 120 hours
• License revocation: Up to 2 years; potential 5-year revocation as a Habitual Traffic Offender under C.R.S. § 42-2-202
• IID: 2 years minimum
• Persistent Drunk Driver designation: Automatic

Fourth or Subsequent Offense (Felony DUI)

• Prison: 2 to 6 years in the Colorado Department of Corrections (up to 12 years with extraordinary aggravating circumstances)
• Parole: 3 years mandatory, with IID required for the entire parole period
• Fines: $2,000 to $500,000
• If probation is granted: 90 to 180 days in county jail as a condition

Collateral Consequences

Beyond the statutory penalties, a DUI conviction can affect your professional licensing, immigration status, employment, child custody arrangements, auto insurance rates, and—for CDL holders—your commercial driving privileges. These downstream consequences are often more significant than the criminal penalties themselves and should factor into every defense strategy.

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Defense Strategies

Every DUI case is built on a chain of evidence—from the initial traffic stop through chemical testing. Each link in that chain presents an opportunity to challenge the prosecution’s case.

Challenging the Traffic Stop

The Fourth Amendment requires officers to have reasonable suspicion to initiate a traffic stop. If the officer lacked a valid basis—weaving within a lane that doesn’t cross lane markings, minor equipment violations used as pretext, or stops based on anonymous tips without corroboration—the entire stop may be unconstitutional. If the stop is suppressed, everything that followed (field sobriety tests, chemical tests, statements) may be excluded from evidence.

Field Sobriety Test Challenges

The three Standardized Field Sobriety Tests (HGN, Walk-and-Turn, One-Leg Stand) must be administered according to protocols established by the National Highway Traffic Safety Administration. Officers frequently deviate from these protocols—giving incorrect instructions, testing on uneven surfaces, failing to account for the subject’s age, weight, injuries, or footwear. When the tests are not administered correctly, their reliability as indicators of impairment is significantly diminished.

Breathalyzer Accuracy

Breath testing instruments must be properly calibrated, maintained, and operated according to Colorado Department of Public Health and Environment regulations. Common issues include machines that are overdue for calibration, operators who lack current certification, mouth alcohol contamination from recent eating, belching, or use of mouthwash, and radio frequency interference. The margin of error on breath testing instruments can be significant—particularly when a BAC reading is near the 0.08% threshold.

Blood Draw Procedures

Blood tests must follow strict chain-of-custody protocols. The draw must be performed by qualified medical personnel, the sample must be properly preserved with the correct anticoagulant and preservative, and it must be stored and transported under documented conditions. Fermentation, contamination, or mishandling can produce artificially elevated results. Independent retesting of the sample—which defendants have a right to request—sometimes reveals significant discrepancies.

Rising BAC Defense

Alcohol takes time to absorb into the bloodstream. A driver whose BAC was below 0.08% while actually driving may test above that threshold 30, 60, or 90 minutes later at the police station. The rising BAC defense argues that the test result reflects the driver’s BAC at the time of testing, not at the time of driving. This defense is particularly relevant when there was a significant delay between the stop and the chemical test.

Medical Conditions and Mouth Alcohol

Certain medical conditions—GERD (gastroesophageal reflux disease), diabetes, and some dietary conditions like ketosis—can produce mouth alcohol or acetone that breath testing instruments may misidentify as ethanol. These conditions can generate falsely elevated breath test results even when the subject has consumed little or no alcohol.

Drug-Specific Defenses

In DUID cases, the prosecution faces the additional burden of proving that a drug actually impaired driving ability—not merely that it was present in the driver’s system. THC, for instance, is fat-soluble and can remain detectable in blood for days or weeks after use, long after any psychoactive effect has dissipated. The 5 ng/mL threshold is a permissible inference, not a per se limit, and can be rebutted with evidence about the individual’s tolerance, the timing of use, and their actual driving behavior.

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Our Experience

Jolie Masterson and Jesse Hall are criminal defense attorneys who handle DUI cases as part of a broader practice that includes homicide, federal drug cases, sexual assault, and other serious felonies. This matters because DUI defense, done well, draws on the same skills: forensic evidence analysis, constitutional law, cross-examination of expert witnesses, and the ability to take a case to trial when the evidence warrants it.

Between them, Jolie and Jesse bring more than 20 years of criminal defense experience to every case. Both served as public defenders before entering private practice—Jolie for seven years at the Colorado State Public Defender’s Office, Jesse for five years as a Deputy State Public Defender handling felony and homicide cases. Both are admitted to the U.S. Supreme Court and are on the Criminal Justice Act panel for the U.S. District Court for the District of Colorado.

Jesse’s background in forensic science and evidence—including published scholarship on cell-tower tracking data—applies directly to DUI cases involving technical evidence challenges. Jolie’s trial record of 48 cases and 18 acquittals reflects the kind of courtroom experience that gives prosecutors reason to negotiate seriously.

Masterson Hall is not a DUI mill processing hundreds of cases on a conveyor belt. We invest the time to investigate the facts, examine the evidence, and identify the defense strategy that gives each client the strongest possible outcome—whether that means negotiating a favorable resolution or taking the case to trial.

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Case Results

DUI — Evidence Suppression Charge: DUI Result: Breath Test Results and Police Observations Excluded, Case Dismissed (multiple cases) Court: Colorado State Court Attorney: Jesse Hall

Jesse Hall has successfully argued that illegal police conduct resulted in illegally obtained breath tests, leading to the exclusion of both the breath test results and all police observations. The courts dismissed these cases entirely.

DUI — Trial Charge: DUI Result: Not Guilty Verdict (multiple cases) Court: Colorado State Court Attorney: Jesse Hall

Jesse Hall has won multiple DUI jury trials, including cases where the defense was that the client was not the driver and cases where the defense was that the client was not intoxicated.

DUI — Sentencing Mitigation Charge: DUI Result: Plea Agreement with No Jail Time (multiple cases) Court: Colorado State Court Attorney: Jesse Hall

In cases where the government sought lengthy jail sentences, Jesse Hall’s mitigation investigation and arguments resulted in plea agreements with no jail time.

Past results do not guarantee future outcomes. Every case is different. These results reflect the specific facts and circumstances of each case.

View all case results →

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Frequently Asked Questions

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Talk to a Defense Attorney

If you have been arrested for DUI, DWAI, or any impaired driving charge in Colorado, contact Masterson Hall for a confidential consultation.

Call (720) 445-5505 to schedule a confidential consultation, or request a consultation online. Your inquiry is confidential.