Marijuana Impairs Driving Longer Than You Think

Texas DWI laws apply to both drunk driving and drugged driving. Someone who is impaired after smoking marijuana can face a DWI charge and serious penalties, even if they don’t get into an accident.

Marijuana continues to grow in popularity as a recreational drug, and some cities around Texas have started to decriminalize small amounts of it. However, as a study from 2022 shows, impairments last longer than many people think. You should never drive immediately after smoking marijuana, and you probably need to wait much longer than expected.

Marijuana Impairment

Marijuana has well-known side effects that impact driving performance, including:

•         Delayed reflexes
•         Impaired judgment
•         Increased fatigue
•         Difficulty maintaining your lane
•         Reduced ability to divide attention

Someone who is high on marijuana could easily get into an accident or at least draw the attention of the police. Officers today are trained on how to notice marijuana use, and they can use a Drug Recognition Expert to put drivers through tests to determine whether you are impaired.

The police might also get a warrant for a blood draw to find out the amount of marijuana you consumed. This evidence could show up later at a criminal trial, where it is very persuasive with juries.

How Long Are You Impaired?

Anyone who smokes marijuana should avoid jumping into a car and turning on the ignition. But how long do you have to wait?

An interesting study published in 2022 analyzed driver performance after consuming cannabis. As reported in the Wall Street Journal, researchers found that up to 50% of those who had consumed THC (the psychoactive component in cannabis) were classified as impaired based on performance in a simulator.

Researchers also asked participants whether they were feeling normal enough to drive. After 30 minutes, around half hesitated. But after 90 minutes, more said they were ready to drive because the effects of THC were wearing off.

Interestingly, driving performance was just as bad after 90 minutes as it was after 30. In essence, those who used THC were overly optimistic about their driving ability. They believed that the effects of marijuana wear off much sooner than they actually did.

How Long Should Users Wait?

Researchers found that the effects of THC began to wear off around 3.5 hours for most people, and by 4.5 hours, most study participants were back to normal.

Is it safe to drive then? The answer is “probably not.”

According to doctors, THC is less predictable than alcohol or other drugs in how it affects a person. You might remain seriously impaired even after four or five hours.

Further, some people develop tolerance to cannabis. Their THC levels remain high, but they show fewer side effects. Nonetheless, having a high THC level in your bloodstream could be introduced as evidence in a DWI trial.

Conservative estimates call for waiting up to 8 or even 12 hours after consuming cannabis or an edible before driving again. It is much better to be safe than involved in a wreck with a high level of THC in your blood. You could face DWI or even intoxicated assault charges.

Defending Against a Cannabis DWI

Tad Nelson is one of the most experienced DWI defense attorneys, who has a unique understanding of the chemistry behind drunk driving. Over the years, he has broadened his practice to include assisting those accused of drugged driving, including cannabis DWI.

Texas laws regarding the legality of marijuana are in flux. Currently, people with qualifying medical conditions can use low-THC cannabis for treatment. And some cities are decriminalizing small amounts of DWI. Nonetheless, it is never safe (nor legal) to drive while you are impaired.

Section 49.10 of the Penal Code states outright that being entitled to use a controlled substance like marijuana is not a defense to a drunk driving charge. You might have a medical reason to smoke cannabis—but not a medical reason to get in a vehicle and drive.

Our legal team can attack the evidence using various techniques. We might challenge the credibility of witnesses, including a Drug Recognition Expert. The blood sample could also be contaminated or have gaps in the chain of custody. Let us review all the facts before settling on the best strategy for your case.

Get Started Today

Your DWI defense begins almost as soon as you are handcuffed and have your license confiscated. Contact Tad Nelson as soon as possible. Our legal team will begin building a defense to obtain the best result for your case as possible.