Drug impairment standards
Colorado DUI and DWAI law applies to alcohol, drugs, or a combination. DUI and DWAI use different impairment standards.
Lawful entitlement to use a drug, a prescription, a laboratory result, and the charged impairment standard are distinct statutory and factual subjects.
Marijuana inference
A properly tested whole-blood result containing at least five nanograms of delta-9 THC per milliliter permits a factfinder to infer that the driver was under the influence of one or more drugs. The inference is not mandatory.
A result below five nanograms does not automatically prevent an allegation, and a result at or above five does not automatically establish every element.
Testing and separate proceedings
Colorado’s expressed-consent provisions describe blood, saliva, and urine testing for drug-related investigations when statutory requirements are met. The requested test and an alleged refusal are distinct subjects.
The criminal court case and DMV administrative process are separate. A positive drug test does not automatically create the same administrative action as an alcohol excess-BAC result.
Common questions
Frequently asked questions
Is five nanograms of THC an automatic marijuana DUI conviction?
No. Colorado law permits an inference from a properly tested whole-blood result of at least five nanograms of delta-9 THC per milliliter, but the inference is not mandatory.
Can an allegation exist below five nanograms?
Yes. A below-five result does not by itself prevent an allegation, and a charge is not the same as a conviction.
Can prescribed medication be involved in DUI or DWAI?
Yes. Colorado’s definitions include drugs, and lawful entitlement is distinct from the charged impairment standard.
Does a positive drug result alone establish impairment?
No. A positive result and the charged statutory impairment standard are distinct subjects.
What drug tests does Colorado expressed-consent law describe?
The statute describes a test or tests of blood, saliva, and urine when its requirements are met.
Can an alleged refusal create a separate DMV action?
Yes. An alleged refusal may become part of the court record and can begin a separate DMV administrative process.
Does a medical-marijuana authorization prevent a DUI allegation?
No. An authorization and the charged statutory impairment standard are distinct subjects.
Official Colorado and federal sources
These official government sources support the factual copy above. Source availability, laws, and agency information can change.
- Colorado General Assembly — Colorado Drunk Driving Laws summary
- Colorado Revised Statutes 2026, Title 42
- Colorado Department of Transportation — Drugged Driving FAQs
- Colorado Department of Transportation — Expressed Consent
- Colorado Department of Public Health and Environment — Alcohol and Drug Testing Laboratories
- Colorado Secretary of State — current 5 CCR 1005-2 testing standards
- Colorado DMV — The DUI Process
- Colorado DMV — The DUI Administrative Process
- NHTSA — Drug-Impaired Driving
Sources checked August 22, 2026. Attorney reviewed August 22, 2026.