Utah Cannabis DUI & the .05 BAC Standard

Last verified: April 2026

The Statute: §41-6a-502

Utah’s DUI law is at Utah Code §41-6a-502. A person violates the statute by operating or being in actual physical control of a vehicle while:

1. Having a blood or breath alcohol concentration of .05 grams or greater; OR
2. Being under the influence of alcohol, any drug, or the combined influence — to a degree that renders the person incapable of safely operating a vehicle.

Subsection (1)(b) is the impairment-based prong — the route prosecutors take in cannabis cases. Subsection (1)(a) is the per se BAC prong, which applies only to alcohol.

A person commits the offense of driving under the influence if the person operates or is in actual physical control of a vehicle while having a blood or breath alcohol concentration of .05 grams or greater, or while being under the influence of alcohol, any drug, or the combined influence, to a degree that renders the person incapable of safely operating a vehicle.

Utah Code §41-6a-502(1)

Penalties Under §41-6a-503

The .05 BAC Threshold — Strictest in the Nation

HB 155 (2017), sponsored by Rep. Norm Thurston, lowered Utah’s per se BAC limit from .08 to .05 effective December 30, 2018. Utah remains the only U.S. state at .05 as of April 2026. The standard tracks the World Health Organization’s recommended limit and follows the practice of most European countries, but it is a sharp departure from the .08 standard adopted nationwide in 2004.

According to KSL Investigators’ 2024 review by Jason Mettmann of the Utah Highway Safety Office, alcohol-related fatalities dropped from 48 (2018) to 27 (2019), spiked during COVID, and the average arrestee BAC remained at 0.15 — three times the legal limit. The cultural overlay matters for cannabis: the same enforcement apparatus that aggressively pursues alcohol impairment also pursues drug impairment.

Cannabis-Specific Impairment: §41-6a-517

Utah Code §41-6a-517 — “Driving With Measurable Controlled Substance” — is the cannabis-specific charge. Subsection (2) provides that, in cases not amounting to a DUI under §502, “a person may not operate or be in actual physical control of a motor vehicle within this state if the person has any measurable controlled substance or metabolite of a controlled substance in the person’s body.” A first violation is a Class B misdemeanor.

Affirmative defenses under §41-6a-517(3) include:

• Involuntary ingestion
• Ingestion under a valid prescription
• Otherwise legal ingestion (the defense relied on by Utah medical cardholders)

Was Utah a “Metabolite” State? Yes — And Partly Still Is.

For years Utah enforced strict zero-tolerance for any measurable cannabis metabolite, including the inactive carboxy-THC (11-nor-9-carboxy-THC) metabolite that persists in urine for weeks after use. That standard was incompatible with a medical program: a patient consuming legally on Saturday could test positive on Wednesday with no active impairment.

With the Medical Cannabis Act, §41-6a-517 was amended to provide an affirmative defense for cannabis lawfully consumed in medicinal dosage form by a registered cardholder. The defense reaches the metabolite-only fact pattern: a card, a pharmacy purchase, no signs of active impairment. If the State proves actual impairment under §41-6a-502(1)(b), the medical-cannabis affirmative defense does not apply — cardholders can still be convicted of impaired driving on the impairment-based DUI prong.

Active hydroxy-THC (the impairing metabolite) and delta-9 THC remain actionable for impairment regardless of card status.

HB 69, HB 395, and HB 203 — Recent Updates

The legislature has continued to refine the cannabis-DUI framework since the Medical Cannabis Act took effect:

• HB 69 (2024) — DUI Testing Amendments (Rep. Ryan Wilcox / Sen. Wayne Harper, signed by Gov. Cox March 13, 2024) revised testing standards to better differentiate active impairment from residual metabolites in medical cannabis patients.
• HB 395 (2024) — DUI Offense Amendments (Eliason / Bramble) adjusted sentencing structure and expungement eligibility for DUI convictions.
• HB 203 (2025) — Cannabis Amendments updated cross-references in the cannabis statutes following the 2023 recodification of Title 26 to Title 26B.

The DRE Program: 155 Drug Recognition Experts

The Drug Recognition Expert (DRE) program is administered by the Utah Highway Patrol. Utah was added to the NHTSA/IACP DEC Program in 1988 and the Utah DPS program began in 1990. As of late 2025, 155 DREs were certified statewide.

Certification involves:

• Two weeks of classroom training
• An 80%-or-higher written exam
• 12 supervised drug evaluations in the field
• A final comprehensive exam

Recertification every two years requires four additional evaluations and eight hours of training. DRE testimony is admissible in Utah courts as expert opinion under Utah Rule of Evidence 702 subject to Daubert-style reliability review. A DRE evaluation typically follows a standardized 12-step protocol and pairs with toxicology results to support an impairment finding.

Workplace Testing: Title 34 and §26B-4-207

The Utah Drug and Alcohol Testing Act at Title 34, Chapter 38 governs private-employer testing. Employers may test only if they maintain a written policy distributed to employees, with management/supervisors also subject to periodic testing. Tests must occur during or immediately after the regular work period. Confirmation testing is required for any positive at a HHS-certified lab using GC-MS or comparable methodology. Section 34-38-9 grants employer immunity for compliance-based actions.

Public-sector cannabis-specific protection at §26B-4-207 prohibits a state or political-subdivision employer from taking retaliatory action against a valid cardholder for failing a marijuana drug test absent evidence of impairment affecting job performance — with carve-outs for federally funded positions, security-clearance positions, and safety-sensitive roles (firefighters, paramedics, EMTs, dispatchers). No equivalent protection exists for private-sector employees. Private employers may maintain zero-tolerance policies and terminate medical cardholders for positive tests.

CDL Drivers Cannot Hold Cards

Commercial driver’s license (CDL) holders are governed by federal Department of Transportation regulations under 49 CFR Part 40, with marijuana metabolite cutoffs of 50 ng/mL initial and 15 ng/mL confirmation. Federal preemption applies regardless of Utah card status. Utah’s Medical Cannabis Act at §26B-4-203 specifically excludes CDL holders from the cardholder pool for this reason.

Practical Guidance

• Wait at least several hours after consumption before driving. Acute impairment from inhaled cannabis typically peaks within 30 minutes and tapers over 2–4 hours; edibles can last considerably longer. There is no Utah-recognized “safe” consumption-to-driving interval, but the longer, the better.
• Cardholders should carry their card — physical or in the EVS app — in case of a stop. The affirmative defense at §41-6a-517(3) is meaningful but must be invoked.
• Refusing a chemical test triggers automatic license consequences under Utah’s implied-consent provision at §41-6a-520, separate from any DUI conviction.
• An open container in the vehicle — even sealed pharmacy packaging that has been opened — can support inferences relevant to impairment charging.

Explore Related Pages

Official Sources

• Utah Code §41-6a-502 — DUI
• Utah Code §41-6a-517 — Measurable Controlled Substance
• Utah Code Title 34, Chapter 38 — Drug and Alcohol Testing
• Utah Code §26B-4-207 — Public-Employee Cardholder Protection