Is it illegal to drive after using marijuana in Tennessee?

Yes, it is illegal to drive after using marijuana in Tennessee. But the law is not always as clear-cut as people expect. Let’s walk through what that looks like on the ground here in Tennessee, because this issue isn’t just about a law, it’s about what happens to real people every day.

A Wake-Up Call After a Night of Relaxation

Imagine this: You stopped smoking weed or haven’t smoked marijuana in years. Maybe not since college. But on a weekend getaway with friends in Nashville, you decide to unwind. You hit a vape pen, eat a gummy, or share a joint at a party. You’re relaxed, laughing, maybe even feeling a little nostalgic. A couple hours pass and you feel “fine” – at least, fine enough to drive back to the Airbnb.

Then come the blue lights.

You’re pulled over. The officer asks where you’re headed, what you’ve been up to. He says you were swerving or didn’t use your blinker. Before you know it, you’re out of the car doing sobriety tests on the side of the road. You think you’re performing okay. But the officer isn’t nodding. He calls in a drug recognition expert.

And just like that, you’re arrested for DUI – even though you haven’t had a drop of alcohol.

Why Is This Happening If Marijuana Isn’t Legal Here?

Unlike states like California, Colorado and some other States, marijuana isn’t legal in Tennessee — not recreationally, and barely medically. But even if it were, Tennessee DUI law (T.C.A. § 55-10-401) makes it illegal to drive if you’re impaired by any substance, legal or not.

That includes:

• Marijuana
• Prescription drugs
• Over-the-counter meds like Benadryl

It doesn’t matter what caused the impairment. What matters is whether the officer believes your mental and physical faculties are compromised. That subjective interpretation is what triggers a marijuana DUI arrest.

What If I Bought it from a Store in Tennessee?

Even if you purchased marijuana or THC-derived products (like delta-8 or delta-9 edibles) from a licensed store in Tennessee, you can still be charged with DUI if you’re impaired while driving. Many of these products are sold legally under hemp laws, but impairment is impairment. The source doesn’t matter—if a law enforcement officer believes your ability to operate a vehicle is compromised, you’re subject to the same DUI laws under T.C.A. § 55-10-401.

This is a common misconception. People think because a product is sold over the counter, it’s “safe” to use before driving. But Tennessee’s DUI statute doesn’t distinguish between legal and illegal substances. It only looks at whether your driving was affected.

But There’s No Breathalyzer for Weed, Right?

Correct. There isn’t a breathalyzer for marijuana. So instead, law enforcement uses:

• Their Senses: often arrests for Drug or DUI for weed begins with the officer smelling the odor of marijuana
• Field Sobriety Tests (walk and turn, one-leg stand, HGN)
• Drug Recognition Expert evaluations
• Blood Test for drugs called Toxicology (TOX) (often with a warrant)

Officers may check your vital signs, ask you to follow a finger with your eyes, or bring their finger close to your nose to see if your eyes “cross” properly. These tests are far from perfect, but they’re still used to justify arrests and court proceedings.

How Long Should I Wait After Using Marijuana to Drive?

The safest bet is to wait at least 24 hours but like a typical attorney’s answer, it depends. Everyone metabolizes THC differently. There is no set THC “legal limit” like the .08 standard for alcohol. Better wait than risk hurting yourself, others and get arrested.

Tennessee law uses a broader standard: whether you are impaired to a degree that affects your ability to drive safely. Officers and prosecutors can argue that impairment lingers well past the point you feel normal again.

What If I Have a Prescription?

Even if you have a prescription for medical marijuana (from another state) or take legal THC-based medication like Marinol, you can still be charged with DUI if it impairs your driving.

What To Do If You’re Pulled Over After Using Marijuana

• Be polite and STFU, don’t answer questions about drug use or anything else that can incriminate you.
• Refuse field sobriety tests and blood tests.
• If arrested, refusal to take a blood test can trigger an Implied Consent Violation under T.C.A. § 55-10-406, leading to license suspension.
• Call a Tennessee DUI focused attorney immediately.

Final Thought: You’re Not Alone

We represent great people who made a single decision they didn’t think would have major consequences. They smoked, vaped, or ingested something and thought they were ok to drive. The police thought otherwise.If this sounds like your situation, call us. At Nash Law, we specialize in marijuana-related DUI cases in Tennessee. We understand the nuances, we challenge flawed evidence, and we know how to protect your rights.

Call 615-NASH-LAW (615-627-4529) or schedule your Free Strategy Session today.

We only help great people fight their DUI charges©️—and we’re ready to fight for you.