How Wyoming’s DWUI law applies to drug impairment
Wyo. Stat. § 31-5-233 covers DWUI by alcohol and by controlled substances, and the standard for drug-related DWUI is different from the BAC-based standard for alcohol. There is no legal per se limit for drugs in Wyoming, the way there is for alcohol at .08%. Instead, the prosecution must prove that you were under the influence of a controlled substance to a degree that rendered you incapable of safely operating a vehicle. That’s a higher burden — and it creates real defense opportunities.
Wyoming is surrounded by states where marijuana is legal. Colorado, Montana, and other states allow recreational use, and Wyoming courts regularly see cases involving people who used marijuana legally across the border and were then stopped in Wyoming. THC metabolites can remain in your bloodstream for weeks after any impairment has passed. A positive blood test for THC does not prove you were impaired at the time of the stop — and we have successfully challenged these cases on exactly that basis.
Prescription medications and DWUI in Wyoming
DWUI charges arising from prescription medication use are more common than most people realize and more defensible than many defendants expect. Taking a prescribed medication does not automatically make you impaired. The prosecution must still prove that the medication affected your ability to drive safely. If you were taking a medication as prescribed, at normal dosage, and your driving was not actually impaired, those are facts that go to the heart of the charge, not just mitigating circumstances.
We examine the toxicology report, the officer’s observations, the field sobriety test performance, and the pharmacological evidence regarding the substance’s effect on driving ability. Expert testimony on drug pharmacology and impairment is often central to the defense in prescription drug DWUI cases.
How we defend drugged driving cases in Wyoming
The defense of a drugged driving case starts with the toxicology evidence. Was the blood draw obtained lawfully? Was the sample handled properly through its chain of custody? Does the laboratory report actually establish impairment at the time of the stop? Or does it merely confirm the presence of a substance? These are distinct questions, and the answer to the last one is often no. A blood test that shows THC metabolites, or a prescribed medication at therapeutic levels, does not establish impairment. We challenge the prosecution’s interpretation of toxicology evidence in every drugged driving case we handle.

