Drug DUI (DUID) in Colorado: Marijuana, Prescriptions and the Law
You had a prescription. Or a medical marijuana card. Or you had not smoked in hours. None of that is a defense by itself under Colorado law — but that does not mean the case against you is airtight. Here is what the statute actually says, and where a drug DUI case is genuinely won or lost.
Figures follow current Colorado statute text, checked September 26, 2026.
One Statute Covers Alcohol, Drugs, and Both Together
Colorado does not have a separate crime for "drugged driving." DUI and DWAI are written to cover alcohol, one or more drugs, or a combination of the two, in the same clauses (C.R.S. § 42-4-1301(1)(a), (1)(b)).
"Driving under the influence" means using alcohol, drugs, or both, to a degree that leaves you "substantially incapable, either mentally or physically, or both mentally and physically, to exercise clear judgment, sufficient physical control, or due care in the safe operation of a vehicle" (C.R.S. § 42-4-1301(1)(f)). "Driving while ability impaired" uses the identical structure, but at a lower bar — the substance only has to affect you "to the slightest degree" beyond your ordinary ability (§ 42-4-1301(1)(g)).
Because both definitions already include "alcohol or one or more drugs, or a combination," a case involving both alcohol and marijuana, for example, is still charged as one DUI or DWAI offense, not two separate crimes stacked on top of each other.
The THC Number, and What It Actually Does
5 nanograms per milliliter is often described as Colorado's marijuana DUI limit. That overstates it.
An inference, not a per se limit
A THC concentration of 5 ng/mL or more of delta-9 THC in whole blood permits — but does not force — an inference that you were under the influence of a drug (C.R.S. § 42-4-1301(6)(b)(III)). There is no "any amount" THC rule in Colorado. Unlike the 0.08 alcohol threshold, which is DUI on its own, the THC number is one piece of evidence a jury weighs, not an automatic finding.
Drug Recognition Experts
Officers trained through Colorado's DRE program, run since 1987 through CDOT's Highway Safety Office, complete 72 hours of classroom instruction and 32 hours of supervised fieldwork before certification. A DRE's conclusions are opinion testimony based on an evaluation, not a chemical measurement, and can be challenged the same way any officer's observations are challenged — through their training records, what was actually observed, and whether the stated conclusion follows from it.
A Legal Prescription Is Not a Defense
Colorado's statute says this directly: being legally entitled to use a drug, including under a medical marijuana card, "shall not constitute a defense" against a DUI or DWAI charge (C.R.S. § 42-4-1301(1)(e)). That covers over-the-counter medication too — the statute draws no line between prescribed, recommended, or store-bought.
The only question that matters is whether you were actually impaired while driving, to the degree the charged offense requires. Whether the substance was legal, prescribed, or recommended by a doctor does not answer that question either way — it is simply not part of the legal test.
The Penalties Are the Same as Alcohol DUI
Because drug DUI is not a separate crime, it carries the same offense-count penalty ladder as any other DUI or DWAI (C.R.S. §§ 42-4-1301, 42-4-1307).
| Offense | Jail | Fine | Community service |
|---|---|---|---|
| First DUI or DUI per se | 5 days to 1 year | $600 to $1,000 | 48 to 96 hours |
| DUI or DWAI, one prior | 10 days to 1 year | $600 to $1,500 | 48 to 120 hours |
| DUI or DWAI, two priors | 60 days to 1 year | $600 to $1,500 | 48 to 120 hours |
| DUI or DWAI, three or more priors | 2 to 6 years (Class 4 felony) | $2,000 to $500,000 | N/A |
How a Drug DUI Case Actually Gets Contested
Because the THC number is a permissible inference rather than a per se limit, the case does not end the moment a lab report comes back at 5 ng/mL or higher. The prosecution still has to convince a jury that you were actually impaired, to the degree the charged offense requires, at the time you were driving — and that opens the same ground alcohol DUI cases turn on: the reason for the stop, how the field sobriety tests were administered and scored, whether the blood draw followed proper procedure and chain of custody, and whether the DRE's specific observations actually support the conclusion reached.
Because the inference is rebuttable and the DRE's evaluation is opinion testimony rather than a chemical measurement, both are proper subjects for cross-examination on the officer's specific training, the exact observations recorded at the time, and whether those observations actually support the conclusion reached — the same way any other officer testimony gets tested at trial.
Express Consent Covers Drug Testing Too
Colorado's Express Consent law is not alcohol-specific. By driving in Colorado, you have consented to a blood, breath, saliva or urine test once an officer has probable cause for DUI or DWAI (C.R.S. § 42-4-1301.1). For a suspected drug case, that usually means a blood draw rather than a breathalyzer, since breath testing measures alcohol, not THC or other drugs.
Refusing that test carries the same two consequences it does in an alcohol case: it is grounds for administrative license revocation on its own, and it is admissible as evidence against you at trial. The revocation lengths and the hearing process are the same either way — see our page on the DMV Express Consent hearing for the 7-day deadline that follows.
Plea Bargaining Limits Apply Here Too
The same restriction that applies to alcohol DUI cases applies to drug DUI cases: a court generally cannot accept a guilty plea to a non-alcohol, non-drug traffic offense from someone charged with DUI or DUI per se, absent a good-faith prosecutorial representation that the evidence does not support the original charge (C.R.S. § 42-4-1301(4)). A reduction to DWAI, or a dismissal, still depends on what the evidence actually shows — which is the reason to have it reviewed early, not after a plea has already been entered.
Local Courts: Arapahoe County
Arapahoe County Justice Center
7325 S. Potomac Street, Centennial, CO 80112. A drug DUI or DWAI is heard the same way an alcohol-based charge is — misdemeanors in Arapahoe County Court, felony-level cases in Arapahoe County District Court, both at this address, in the 18th Judicial District.
Digital evidence in your case
A drug DUI case usually turns on the officer's body-camera and dash-camera video of the stop and the DRE evaluation, the lab's blood test records and chain-of-custody paperwork, and sometimes phone data if it becomes relevant to timing or use. We request and review that record, with forensic examination handled by our partner lab under attorney direction when it needs closer analysis.
Learn about digital forensics at our firmOther DUI Topics
Drug DUI FAQs
Straight answers, with the statute they come from
Related Pages
This page is general information about Colorado law, not legal advice for your situation, and reading it does not create an attorney-client relationship. The legal statements here were checked on September 26, 2026.
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