Marijuana DUI in Virginia: Why These Cases Are Harder for the Commonwealth Than They Look

Everyone understands the alcohol side of a DUI. Blow a .08 or higher, and the Commonwealth has a number that, by itself, proves the case after a proper stop. Marijuana does not work that way, and a lot of drivers charged with a marijuana-only DUI assume they are in the same boat as someone who blew over the limit. They are not, and the difference matters.

There Is No Number That Proves Marijuana Impairment

Virginia Code § 18.2-266 makes it illegal to drive while under the influence of alcohol, or under the influence of a narcotic drug or self-administered intoxicant to a degree that impairs safe driving. Alcohol gets a per se number: 0.08 percent blood alcohol content, full stop. The statute also lists specific per se blood-concentration thresholds for a handful of controlled substances, like cocaine and PCP. Marijuana is not on that list. There is no blood THC level in Virginia at which a driver is automatically guilty, the way a driver is automatically guilty at 0.08 BAC.

That is not an accident of drafting. It reflects the actual science. THC does not clear the body, or affect the brain, the way alcohol does. A regular user can carry an active THC level well after any impairing effect has worn off, while an infrequent user can be meaningfully impaired at a level that would mean nothing for someone who uses daily. Blood THC concentration simply does not correlate with how impaired a person actually is behind the wheel, and researchers have said as much for years. That means a lab report showing THC in a driver's blood tells the fact-finder a substance was present. It does not tell them the driver was too high to drive.

What the Commonwealth Actually Has to Prove

Without a per se number, a prosecutor in a marijuana-only DUID case has to build impairment the hard way: driving behavior before the stop, the officer's observations, performance on field sobriety tests that were never validated for marijuana the way they were for alcohol, and often an admission that the driver had used marijuana at some point that day. Every one of those pieces is contestable. Bad driving can have a dozen explanations that have nothing to do with marijuana. Field sobriety tests were designed and validated around alcohol impairment, not cannabis, which leaves plenty of room to challenge what a stumble or a missed count actually proves. And an admission to using marijuana earlier in the day is not the same thing as an admission to being impaired at the moment of driving.

Put together, a marijuana-only DUID case often comes down to an officer's subjective read of a driver's behavior, dressed up with a blood test that cannot do the work the Commonwealth needs it to do. That is a very different case than an alcohol DUI with a breath test result, and it should be defended differently.

Why My Background as a Prosecutor Matters Here

I did not learn how these cases get built by reading about them. I prosecuted felony and misdemeanor DUI cases for the Commonwealth, and I attended Commonwealth-sponsored DUI prosecution training alongside the prosecutors who try these cases across Southside Virginia today. I know how a marijuana DUID case gets put together on the other side of the table: what an officer is trained to document, what a prosecutor needs to fill the gap left by the lack of a per se THC standard, and where that case is usually weakest. I use that same knowledge now to take those cases apart for my clients. Additionally, I served as the Deputy Director of Virginia NORML and assisted clients seeking medical cannabis dispensary licensure in the Commonwealth; I am well versed in cannabis products, their effects, and the science behind it.

Representing Clients Across Southside Virginia

I handle DUI and DUID cases in Pittsylvania County, Danville, Henry County, Martinsville, and Patrick County. Each of these courts has its own tendencies, and knowing the docket, the prosecutors, and the officers who work these stops in this area is part of what a local defense requires.

Don't Blow It!!

A marijuana DUI charge is serious, and the consequences, from license suspension to a permanent criminal record, are real. But a marijuana-only case is not the automatic loss some drivers assume it is, and it deserves a defense built by someone who has been on both  sides of these cases, as prosecutor and defense. When it comes to picking your DUI defense attorney, don't blow it. Call Rouleau Law, PLLC today for a free consultation.

This article is for general informational purposes only and does not constitute legal advice. Reading it, or contacting our office through it, does not create an attorney-client relationship. Every case depends on its own facts, and no outcome, including the outcomes described or implied here, can be guaranteed. Attorney Daniel Rouleau is responsible for this Ad, and not representing himself as specially qualified in DUI defense. Past results do not predict or guarantee similar results in any future case.