Can I Be Charged with a Marijuana DWI in Texas?

Yes, if you drive under the influence of marijuana in Texas, you could get a DWI. And that’s not just because the substance is illegal in this state – even in places where recreational marijuana use has been legalized, criminal charges can arise when someone operates a vehicle while affected by it. The reason you can face a DWI is that the “I” in DWI stands for “intoxicated,” which applies to more than just alcohol.

Can I Be Charged with a Marijuana DWI in TexasUnder Texas Penal Code § 49.01, a person is considered intoxicated when their normal faculties are impaired by any substance. That includes marijuana.


As mentioned above, intoxication is when someone’s mental or physical faculties are compromised by the introduction of a substance into their body. When a person consumes marijuana, the substance travels through their system and to their brain.

The resulting chemical reaction can lead to several effects including, but not limited to:

  • Euphoria
  • Relaxation
  • Disorientation
  • Altered sense of time
  • Impaired body movement

These bodily changes can impair a person’s judgment, coordination, and reaction time – all of which are necessary to drive safely. Thus, when these faculties are decreased, and the individual gets behind the wheel, they can be considered in violation of Texas’s DWI law and face an arrest and criminal charge.


Texas does not have a separate statute for marijuana DWIs. Therefore, the same laws for alcohol-related offenses also apply to those involving cannabis. Thus, the penalties for a marijuana DWI are the same as those for an alcohol DWI.

To illustrate, below are the penalties that can be imposed for a Texas DWI conviction:

  • First offense:

Class B misdemeanor

    • 72 hours to 180 days in jail and/or
    • Up to $2,000 in fines
  • Second offense:

Class A misdemeanor

    • 30 days to 1 year in jail and/or
    • Up to $4,000 in fines
  • Third offense:

Third-degree felony

    • 2 to 10 years of imprisonment and/or
    • Up to $10,000 in fines


One of the tricky things about marijuana DWI matters is that the techniques used to detect alcohol levels and impairment do not translate well into detecting marijuana levels and impairment.

Take, for instance, the Standardized Field Sobriety Tests (SFSTs) administered during the initial DWI stop. These tests have been validated to determine alcohol impairment, but not marijuana impairment. In a study by RTI International, researchers found that SFSTs did not accurately indicate intoxication by marijuana.

Additionally, roadside breath tests are not designed to measure THC levels. However, various labs are in the process of developing devices that can. Still, even if officers could get a reading of the amount of THC in a driver’s body, other issues arise, which we’ll discuss more later.

In a DWI matter, law enforcement officials do not rely solely on SFST or roadside breath test results to justify an arrest or build their cases. They also turn to chemical tests. Yet, blood and urine analyses may not necessarily hold the same weight in a marijuana-related DWI as they do in an alcohol-related DWI.

One of the reasons is the way the two substances behave. Alcohol is absorbed by the blood and quickly leaves the body. In contrast, marijuana is absorbed by fatty tissues, which means the substance can be stored in the body for some time. According to the National Institute on Drug Abuse, marijuana can be detected in a person’s system for days or weeks.

Thus, a chemical test might indicate the presence of marijuana in a person’s body. However, the results do not show when the individual used the substance. Therefore, the driver might not have been under its influence at the time of the alleged offense. Remember, the state must prove that the defendant was intoxicated while driving, not just that they had marijuana in their system.

Also, THC (the psychoactive compound in cannabis) might be in the person’s system, but that does not necessarily mean that they were impaired. The RTI researchers found that THC levels do not reliably indicate intoxication. It is for this reason that many states, including Texas, do not have a per se law for marijuana-related DWIs. With an alcohol-related offense, a person is considered intoxicated if their blood alcohol concentration (BAC) was 0.08 or more.

Because of these challenges, a Drug Recognition Expert (DRE) is typically brought in to evaluate the driver. The DRE puts the driver through a series of tests, such as an interview and eye exam, to determine whether the individual was intoxicated.


If you have been accused of driving while intoxicated by marijuana, you can fight the allegations. As noted above, various challenges exist in these matters, and exposing them could weaken the prosecutor’s arguments.

Speak with an attorney about your case right away. They can examine the details to determine what defenses can be raised on your behalf.

Our Dallas team at Deandra Grant Law is prepared to get started on your case and seek a favorable outcome.

Please schedule a consultation by calling us at (214) 225-7117 or contacting us online today.

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