Early one morning this March, a Scottsdale officer said he watched Dillon Brooks weave across the lanes several times, pulled him over, and reported that the car smelled like a dispensary. Brooks denied recent marijuana use. His breath test came back at 0.00, no alcohol. He was arrested anyway on suspicion of DUI, a blood sample was taken, and he faces two marijuana-related DUI counts while the results are pending.
A marijuana DUI on a clean breath test is its own animal, and it is one of the harder cases for a prosecutor to prove. Here is how Florida handles a weed DUI, and why the science cuts the way it does.
This is general commentary on a publicly reported case that has not been resolved. An arrest is not a conviction, Mr. Brooks is presumed innocent, this is not legal advice, and The Safir Lawyer does not represent him.
A 0.00 breath test means nothing in a weed case
The breath machine measures alcohol and only alcohol. A 0.00 rules out a drinking case and says nothing about marijuana. Florida’s DUI law reaches impairment by a controlled substance, so a drug DUI can move forward on a perfectly clean breath sample. The zero is good news on the alcohol charge and irrelevant to the drug one.
Florida has no THC limit, and that is the heart of the fight
For alcohol there is a bright line at 0.08. For marijuana there is no legal limit in Florida at all. The State cannot point to a number and call you impaired. It has to prove that your normal faculties were impaired by the marijuana at the time you were driving, and that is hard to do with confidence.
A positive test does not show impairment
This is the crux. THC and the compounds it leaves behind can linger in the body for days or even weeks after use, long after any effect on driving is gone. So a blood or urine test that comes back positive tends to show that a person used marijuana at some point, not that they were high behind the wheel. The gap between presence and impairment is wider with marijuana than with almost anything else, which is exactly why these cases are defensible.
The smell of marijuana and the stop
The odor of cannabis often drives both the stop and the search. With medical marijuana legal in Florida, the smell alone carries less weight than it once did, and the lawfulness of the stop and search is always worth testing. A weak basis for the stop can take the whole case down with it.
A medical card is not a defense, and old use still shows
Two things people get backward. A medical marijuana card does not immunize you. If you were impaired, it is still a DUI. At the same time, a claim like the one in the news, that the last use was months ago, lines up with the science rather than against it, because marijuana can show on a test long after it stops affecting you. Old use that still registers is the whole reason a positive result does not equal impairment.
What this means in Florida
A marijuana DUI on a 0.00 breath test is often the most defensible DUI there is. There is no number, the roadside evidence is subjective, and no test can tie THC in your blood to impairment at the wheel. I trained on the toxicology instruments and I am NHTSA qualified on the field tests, so this is the ground I work, and on a weed case the State usually has less than it sounds like.
Charged with a DUI in the Tampa Bay area?
A marijuana DUI on a clean breath test is often the most defensible kind, because no test ties THC to impairment at the wheel. Let’s look at what they really have.
About the author
Rory Safir is one of a handful of ACS-CHAL Forensic Lawyer-Scientists in Florida, an NHTSA qualified field sobriety instructor, and a former Assistant Public Defender in Tampa. He trained on the same gas chromatography instruments the State labs use, which is why he reads breath and blood evidence the way an analyst does.
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Common Questions
Can you get a DUI for marijuana in Florida with a 0.00 breath test?
Yes. The breath machine only measures alcohol, so a zero rules out a drinking case and says nothing about marijuana. A drug DUI can proceed on a clean breath sample if the State can prove impairment.
Is there a legal THC limit for driving in Florida?
No. Unlike the 0.08 limit for alcohol, Florida sets no per se level for marijuana. The State must prove that the marijuana impaired your normal faculties while you were driving.
Does a positive marijuana test prove I was high while driving?
No. THC and its byproducts can linger for days or weeks after use. A positive blood or urine test usually shows past use, not impairment at the time of driving.
Does a medical marijuana card protect me from a DUI?
No. A medical card does not immunize you. If marijuana impaired your ability to drive safely, it can still be charged as a DUI in Florida.