Cannabis and Driving: DUI Laws You Need to Know
Driving under the influence of cannabis is illegal in every state, including states where cannabis is legal. Here's what you need to know about cannabis DUI laws.
Cannabis DUI Is Illegal Everywhere
Driving while impaired by cannabis is illegal in all 50 states and D.C., including every state where cannabis is legal. Cannabis legalization does not mean you can drive while under the influence, even in states like Colorado or California. This is one of the most important rules to understand.
How Cannabis DUI Laws Work
Unlike alcohol, there is no universally agreed-upon THC level that constitutes impairment. States handle this differently:
- Per se limits: Some states (Colorado, Washington, Montana, Ohio) set a legal THC blood limit (usually 5 ng/mL). Being over this limit is automatically a DUI, regardless of actual impairment.
- Zero tolerance: Some states have zero-tolerance policies where any detectable THC results in a DUI.
- Impairment-based: Many states use an impairment-based standard where an officer must demonstrate the driver was impaired through field sobriety tests, drug recognition expert evaluation, and other evidence.
The challenge with THC testing is that THC can remain in your blood for days or weeks after use, even when you're no longer impaired. This means a blood test may show THC presence long after the effects have worn off.
Consequences of a Cannabis DUI
A cannabis DUI carries serious consequences similar to an alcohol DUI:
- First offense: Fines ($500-$5,000+), license suspension (30 days to 1 year), possible jail time, mandatory drug education
- Second offense: Increased fines, longer license suspension, likely jail time, vehicle interlock possible
- Subsequent offenses: Felony charges possible, significant jail time, extended license revocation
A DUI stays on your record and can affect employment, insurance rates, and travel (some countries deny entry to people with DUI convictions).
How to Stay Safe
- Never drive while impaired. If you've consumed cannabis, don't drive. Period.
- Wait long enough. THC impairment typically lasts 2-4 hours after smoking/vaping and 4-8 hours after edibles. When in doubt, wait longer.
- Use rideshare services. Uber, Lyft, or taxis are your best friend in legal cannabis states, especially while traveling across state borders.
- Designate a sober driver. Same principle as with alcohol.
- Don't consume in the car. Even as a passenger, consuming cannabis in a vehicle is illegal in most states. Keep products sealed and in the trunk.