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Driving While Intoxicated or (DWI) on marijuana cases are more rare and can be difficult for the State to prove in court. Police officers in Houston or Harris County make arrests for Driving While Intoxicated on marijuana charges when they believe there is probable cause to believe the person is intoxicated and that the intoxication has occurred because of smoking marijuana or ingesting some THC product. If you or a loved one has been charged with DWI in Houston or Harris County, call us now for a free consultation.

What is DWI on Marijuana?

Driving While Intoxicated on Marijuana is not specifically outline in the Texas Penal Code but it falls under one of the definitions of intoxication and regular DWI under Texas Penal Code 49.04.

How is Intoxication defined?

(2) "Intoxicated" means: (A) not having the normal use of mental or physical faculties by reason of the introduction of alcohol, a controlled substance, a drug, a dangerous drug, a combination of two or more of those substances, or any other substance into the body; or (B) having an alcohol concentration of 0.08 or more.

The key language here is the not having the normal use of mental or physical faculties by reason of the introduction of a drug. THC which is short for tetrahydrocannabinol, the active ingredient in marijuana, is classified as such a drug or substance which can cause you to not have the normal use of mental or physical faculties.

Is there a specific amount of marijuana that is illegal to have in your system while operating a motor vehicle?

No. In Texas there is no specific amount of marijuana that is deemed to be illegal to have in your system while operating a motor vehicle. The State must prove that you lost the normal use of your mental or physical faculties to prove intoxication in a DWI marijuana case.

If the police take a sample of your blood and send it to the DPS or other lab for drug testing then you may get a few types of results. People who have smoked regular marijuana recently and are still under the active effects of THC will get a return for what they call Delta-9 THC. A Delta-9 THC content in your blood indicates that the marijuana may be altering your state of mind.

There is also a type of THC called THC metabolite.

THC metabolite refers to the chemical produced when the body breaks down delta-9-tetrahydrocannabinol (THC), which is the main psychoactive compound in marijuana. THC metabolites can be detected in the blood and are commonly used as markers in toxicology testing to determine recent marijuana use. The presence of THC metabolites in the blood can indicate recent use, even if the effects of the drug have worn off. However, the specific levels and detection time of THC metabolites in the blood can vary based on several factors such as frequency and amount of use, body metabolism, and individual differences.

What is the punishment for a DWI on Marijuana?

A DWI on marijuana that has no other aggravating factors is a Class B Misdemeanor and has a maximum punishment of 180 days in jail and up to a $2,000 and a minimum punishment of 72 hours in jail and up to 2 years of probation.

A State Traffic fine may also be issued in the amount of $3,000 for first time DWI cases and $6,000 with a result of 0.15 or greater.

Frequently Asked Questions


Can you get a DWI for marijuana in Texas?
Yes. Texas Penal Code §49.04 makes it illegal to operate a motor vehicle in a public place while intoxicated, and "intoxicated" includes not having the normal use of mental or physical faculties by reason of a drug or controlled substance — which includes marijuana or THC. There is no per se legal limit for THC the way there is a 0.08 limit for alcohol, so the State must prove impairment.
How does the State prove marijuana impairment?
Unlike alcohol, there is no reliable number that establishes marijuana intoxication. Prosecutors rely on the officer's observations, the standardized field sobriety tests, admissions, and sometimes a blood test showing the presence of THC. Because THC can remain detectable long after any impairing effect has passed, the presence of THC in the blood does not by itself prove you were impaired while driving.
What is the punishment for a marijuana DWI?
A first marijuana DWI is generally a Class B Misdemeanor — 0 to 180 days in jail and up to a $2,000 fine, with the same enhancements and State Traffic fines that apply to alcohol DWIs. Penalties increase for repeat offenses, a child passenger, or an accident causing injury.

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