What happens if you are arrested for DWI after smoking marijuana?

By Jose Ceja
Managing Attorney

Marijuana usage is increasing throughout the country as it is becoming more socially acceptable. Although marijuana is still illegal in Texas, a growing number of states have passed laws legalizing recreational marijuana. In the Houston area, the number of marijuana-related DWI arrests is increasing. Contrary to what some people believe, you can be convicted of DWI if you are driving while stoned, although it is typically a more difficult case for prosecutors to prove.

In most DWI cases, the central issue is whether a defendant was intoxicated (the State must prove all other elements of the offense, such as whether a “vehicle” was involved in the crime, but the intoxication offense is usually the main element at issue in a DWI trial). But what is considered intoxication in a marijuana-related DWI?

“Intoxication” is a defined term under Texas Penal Code 49.01(2) and means that a person had an alcohol concentration of 0.08 or higher, or did not have the normal use of his or her mental or physical faculties by reason of the introduction of alcohol, a controlled substance, a drug, a dangerous drug or a combination of substances. In a DWI case, prosecutors will attempt to prove one or both of these definitions of intoxication.

Of course, in a case where a driver was only smoking marijuana, prosecutors won’t be able to prove an alcohol concentration of 0.08 or higher, so that leaves the sole option of attempting to prove a person is intoxicated by showing a loss of normal use of mental or physical faculties due to smoking or marijuana or the consumption of THC edibles.

What constitutes a “loss of normal use” is not defined. To convince a jury that a suspect is intoxicated, the State of Texas will typically admit videos showing the defendant during the traffic stop and DWI investigation, and introduce testimony from the police officer who will describe what he saw or smelled, what was consistent with intoxication. Additionally, during the investigation police officers will often use Drug Recognition Experts (DREs), who are police officers with special training, and who claim to be experts who can detect people impaired by drugs and or alcohol by using a 12-step evaluation.

Blood draws in marijuana DWI cases (which test for metabolites of marijuana) can be more complicated than DWIs involving alcohol.  For one thing, there is no marijuana metabolite level where an individual would be considered to be legally intoxicated (a handful of States have set intoxication levels for marijuana in DWI cases, but Texas is not one of them). Therefore, prosecutors will often attempt to present the testimony of experts trained in toxicology who will attempt to convince a jury that at a certain level, a defendant would have been intoxicated.

An experienced DWI attorney should be ready to point out the problems with a claim like this. First, unlike alcohol, marijuana does not metabolize linearly. This means that while it is sometimes possible to accurately estimate what a driver’s blood alcohol level would have been, it is much more difficult to estimate a driver’s THC metabolite level at the time he was behind the wheel. For DWI investigations, Texas is a “time of driving” state, meaning that it doesn’t matter what a THC-metabolite level was at the time the blood was drawn – it only matters what it would have been at the time of driving. Additionally, an experienced user of marijuana can have very high levels of metabolites and not lose the normal use of his mental or physical faculties.

Of course, it is a bad idea to drive while under the influence of any substance, including THC. But if you are pulled over after having smoked marijuana, it is a good idea to refuse to answer questions about whether you smoked and how long ago you smoked. Proving a timeline and intoxication in a DWI case will be much easier if you provide police with evidence to use against you.

DWIs are very technical cases and DWIs involving controlled substances like marijuana present even more complex and unique issues. It is very important that you hire a skilled DWI attorney to represent you. Attorney Jose Ceja has studied the science of DWI blood testing extensively and understands the issues involved in marijuana and THC DWI cases. If you are arrested for driving under the influence of THC anywhere in the Greater Houston area, called Ceja Law Firm for a free consultation.

About the Author
Jose Ceja is the managing attorney of Ceja Law Firm. He has practiced law since 2007 and has devoted his career to the practice of criminal law. Mr. Ceja began his legal career as a felony drug prosecutor, where he prosecuted drug, gang, and violent offenses. Mr. Ceja has first or second chaired almost 100 trials, including murders, drug cases, DWIs, and assaults. In his career as a defense attorney, he has regularly obtained dismissals, not guilty verdicts, and grand jury “no bills” in a wide variety of cases.