Can I Get a DUI for Driving Under the Influence of Marijuana in Colorado?

Yes. Marijuana is legal for adults in Colorado, but driving after using it is not. Every year, drivers are arrested and charged with a marijuana DUI, and many of them are surprised to learn that legal use offers no protection at all on the road.

What makes these cases different from alcohol cases is how impairment gets proven. That difference matters, and it can work in your favor.

Is a Marijuana DUI the Same as an Alcohol DUI in Colorado?

The charge comes from the same statute. C.R.S. § 42-4-1301 covers driving under the influence of alcohol, one or more drugs, or a combination of both. Marijuana counts as a drug for this purpose.

You can face two levels of charge:

• DUI: Marijuana left you substantially incapable, mentally or physically, of safely operating a vehicle.
• DWAI: Marijuana affected your ability to drive to the slightest degree.

Both are usually misdemeanors. As with alcohol, a fourth or later offense becomes a class 4 felony, and prior DWAI convictions count toward that total.

What Is the 5 Nanogram THC Limit in Colorado?

This is where marijuana cases split from alcohol cases. Colorado law says that if your whole blood contains five nanograms or more of delta-9 THC per milliliter, that fact gives rise to a permissible inference that you were under the influence of one or more drugs.

A permissible inference is not the same as a per se limit:

• Per se (alcohol): At 0.08 BAC, the number by itself establishes the violation.
• Permissible inference (marijuana): At 5 nanograms, a jury is allowed to infer impairment. It is not required to.

The prosecution still has to prove you were actually impaired. The Colorado Department of Transportation explains the same point from the other direction: a driver can be arrested and cited based on documented impairment even with a blood level below 5 nanograms.

How Do Police Prove a Marijuana DUI?

Because the number alone does not settle the case, prosecutors build these cases on observations. Evidence often includes:

• Driving behavior such as weaving, speeding, or a traffic violation
• The odor of marijuana or paraphernalia in the vehicle
• Bloodshot eyes, slow speech, or delayed responses
• Performance on roadside sobriety tests
• Statements you made about using marijuana
• An evaluation by an officer trained as a drug recognition expert
• Blood test results

Note that a marijuana DUI is a blood case, not a breath case. There is no roadside device that measures THC the way a breathalyzer measures alcohol.

Does a Medical Marijuana Card Protect You?

No. Colorado law is explicit that being legally entitled to use a drug, including medical or recreational marijuana, is not a defense to an impaired driving charge.

The same goes for tolerance. Frequent users often argue they are unaffected at levels that would impair someone else, and there is real science behind that concern, since THC can linger in the blood of a regular user long after any effect has worn off. That argument belongs in a defense strategy, but it is not a shield against being charged.

What Happens to Your License After a Marijuana DUI?

Here is a nuance that trips up a lot of drivers. Colorado’s express consent law requires you to submit to testing when an officer has probable cause. But the DMV’s administrative revocation process is narrower than the criminal case.

According to the Colorado Department of Revenue, an express consent hearing looks at two questions: whether you drove with a BAC of 0.08 or higher, or whether you refused testing.

In practice, that means a THC-only case does not trigger an immediate express consent revocation the way a 0.08 alcohol result does. Refusing the blood test is a different story, and a first refusal carries a one-year revocation on its own. A conviction in criminal court can still bring license consequences, so this is not a free pass.

If alcohol is also involved and your BAC hits 0.08, the standard administrative process applies, including the 7-day deadline to request a hearing.

Can You Get a DUI Hours After Using Marijuana?

Yes, and edibles are a common way people get caught off guard. Smoking produces effects within minutes, so users tend to have a rough sense of when they are affected. Edibles work slower, sometimes taking an hour or more to peak, and the effect can last well into the evening.

The result is a driver who feels fine when they get behind the wheel and becomes impaired mid-drive. There is no reliable formula for how long to wait, because it depends on the dose, the product, your tolerance, and your metabolism.

Timing cuts the other way at the blood draw, too. Blood is usually taken well after the stop, so the number on the lab report reflects a moment other than when you were driving. That gap is often central to the defense.

What Are the Penalties for a Marijuana DUI Conviction?

Penalties track the alcohol DUI structure. A first DUI conviction can bring:

• 5 days to 1 year in jail, often suspended in favor of probation
• $600 to $1,000 in fines, plus costs and surcharges
• 48 to 96 hours of community service
• License revocation and required substance evaluation and education

Repeat offenses carry mandatory minimum jail: 10 days on a second offense and 60 days on a third.

How Can You Defend a Marijuana DUI Charge in Colorado?

These cases are often more defensible than alcohol cases, precisely because the number proves less. Common defense angles include:

• Challenging the stop. Without reasonable suspicion for the stop, evidence gathered afterward may be suppressed.
• Attacking the impairment evidence. Roadside tests were designed around alcohol and can be affected by nerves, injuries, or conditions at the scene.
• Questioning the blood draw. Collection, storage, and lab handling all create room for error.
• Explaining the THC level. Blood is drawn well after driving, and levels in a regular user may say little about impairment at the wheel.

A not-guilty verdict is possible even in cases with blood levels above the 5 nanogram threshold, which shows how much the impairment evidence matters.

Talk to a Lawyer About Your Colorado Marijuana DUI Charge

A marijuana DUI charge rests on an inference, not a fixed number, and that gives a defense real room to work. What you do early, especially around testing and statements, shapes your options later.

Dawson Law handles DUI and DWAI cases involving alcohol, marijuana, and other drugs throughout Boulder and the Front Range. Contact us to review the stop, the testing, and your defense.