Colorado DUI of Marijuana
(42-4-1301 C.R.S.)

Can I legally drive in Colorado after smoking marijuana?

Under 42-4-1301, C.R.S., it a crime to drive under the influence of, or while you are ability impaired by, drugs and/or alcohol. This includes ALL drugs—even legal ones, such as marijuana.

There is no separate code section for Colorado DUI marijuana or Colorado DWAI marijuana. Regular DUI and DWAI laws apply. The only significant differences between drunk driving and driving on marijuana are:

  • Colorado has no strict “legal limit” for marijuana at which you are automatically considered too stoned to drive, and
  • If you are arrested for DUI or DWAI based on marijuana use, the officer can require you to take a DUI blood test (or a saliva or urine test) instead of a DUI breath test.

To help you better understand Colorado laws on driving stoned, our Colorado DUI defense lawyers discuss the following, below:

1. What is DUI of marijuana in Colorado?

You drive under the influence (DUI) of marijuana in Colorado when as a result of consuming marijuana you are substantially incapable, mentally and/or physically, to safely operate a vehicle. Under 42-4-1301, C.R.S., DUI of marijuana is usually a misdemeanor.

Unlike alcohol, there is no DUI “per se” of marijuana. DUI of drugs must be proved by objective evidence that were unable to drive safely. However, it is a permissible inference that you drove under the influence of marijuana if your blood contained 5 nanograms or more of delta 9-tetrahydrocannabinol (THC) per milliliter.1 THC is the active ingredient in most strains of marijuana.2

But even this amount of THC in the blood is not conclusive. The best Colorado DUI lawyers can challenge it in court. To prove you guilty of DUI of marijuana, the prosecutor will need to show that you were actually too stoned to drive safely. Such evidence might include:

  • You violated Colorado traffic laws,
  • You were weaving in and out of your lane,
  • You drove too fast or too slow,
  • You appeared stoned (bloodshot eyes, slurred speech),
  • The officer smelled marijuana in the car,
  • There was marijuana paraphernalia in the vehicle (e.g., rolling papers, a bong, a joint clip, etc.), or
  • Marijuana was found in your car.

However, the mere fact that you had a medical marijuana registry card does not by itself, give the officer the right to insist you take a blood test.3 And it cannot be used as part of the prosecutor's case-in-chief against you4.

2. What is DWAI by marijuana in Colorado?

You drive while ability impaired (DWAI) by marijuana when weed affects you in “the slightest degree.” This means that you are less able mentally and/or physically to safely operate a vehicle than you ordinarily would have been. Under 42-4-1301, C.R.S., DWAI marijuana is usually a misdemeanor.

It doesn't take much impairment in order to be guilty of DWAI. Unlike alcohol, however, there is no test that can establish a presumption that you were not stoned.5 If you are lawfully arrested on suspicion of DWAI of marijuana, the amount of THC in your blood will be just one factor for the jury to consider.

3. How much marijuana is too much?

Colorado has no set limit for how much marijuana can be in your system when you drive. The effect of marijuana can vary depending on many factors, including:

  • The strain of marijuana,
  • The strength of the weed,
  • The mode of administration (e.g., smoked, eaten, vaped, or tincture),
  • Other substances in your system,
  • Whether you have eaten, and
  • Your prior experience with marijuana.

However, a jury is entitled to presume you were DUI of marijuana if a DUI chemical test showed 5 nanograms or more of THC per milliliter of your whole blood.

4. Do I have to take a DUI blood test?

By driving in Colorado, you give your “express consent” to take a chemical test if you are lawfully arrested for DUI or DWAI.6 This does not refer to the roadside preliminary breath test an officer may ask you to take after a traffic stop.7 Unless and until you have actually been arrested, you are not obligated to take a chemical test.

If you are actually arrested, however, refusing a Colorado DUI chemical test has serious consequences. If alcohol use is suspected, you will be offered your choice of a DUI breath test or DUI blood test. If, however, the officer reasonably believes you were using drugs, you may be required to take a blood test instead or as well.

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5. Penalties for DUI / DWAI of marijuana

Consequences of Colorado DUI marijuana are the same as for DUI of alcohol. Consequences of Colorado DWAI marijuana are the same as for DWAI of alcohol. They can include:

  • Jail time (especially if you have a prior drunk/drugged driving conviction),
  • A fine, 
  • Loss of your Colorado driving privilege (especially for DUI),
  • Ignition interlock restriction once you get your driver license back, and
  • Increased insurance costs.

6. Defenses to DUI / DWAI marijuana

The best defenses to Colorado DUI marijuana charges depend on the facts of your case. However, defenses our skilled Colorado DUI attorneys commonly raise include (without limitation):

  • The officer had no probable cause to pull you over,
  • There was no reasonable basis for suspecting you of drug use or giving you a blood test,
  • The officer did not properly advise you of your rights,
  • Improper procedures were used in your DUI blood test,
  • Your driving was not affected by marijuana,
  • You drove poorly for another reason totally unrelated to marijuana use (such as you were tired, sick or distracted).

Call us for help…

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Were you charged with DUI of marijuana in Colorado? Our compassionate and experienced Colorado DUI attorneys have years of defending drugged driving charges.

Contact us for a free consultation to discuss your case and possible defenses. Find out why were are considered among the best DUI lawyers in Colorado.

Communities we serve include Denver, Colorado Springs, Aurora, Fort Collins, Lakewood, Thornton, Arvada, Westminster and Centennial. You can use the form on this page, or call us at our convenient Denver home office, located at:

Colorado Legal Defense Group
1400 16th Street
16 Market Square
Denver CO 80202
(720) 955-6112


Legal references:

  1. 42-4-1301(6)(a)(IV), C.R.S.
  2. So-called high cannabidiol (CBD) strains of marijuana contains relatively little THC. It is often consumed by users of medical marijuana who do not want to get high. It is still unlawful, however, to drive after consuming high CBD weed if it affects your driving.
  3. 42-4-1301(6)(k), C.R.S.
  4. 42-4-1301(6)(j), C.R.S.
  5. See 42-4-1301(6)(a)(I). If at the time you alleged alcohol, your blood alcohol content was .05% or less, it shall be presumed that you were not under the influence of alcohol and that your ability to operate a motor vehicle was not impaired by alcohol.
  6. 42-4-1301.1, C.R.S.
  7. Colorado state troopers have begun experimenting with a roadside saliva test for marijuana. However, as yet this test has not been officially adopted as preliminary field sobriety test.

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