Texas under Texas Penal Code § 49.01(2) defines intoxicated as “not having the normal use of mental or physical faculties by reason of the introduction of alcohol” into the body. The definition also includes intoxication by reason of the introduction of “a controlled substance, a drug, a dangerous drug, a combination of two or more of those substances, or any other substance into the body.”

While driving while intoxicated (DWI) is a crime commonly associated with drunk driving and people being under the influence of alcohol, it is important to understand that law enforcement in Texas can arrest a person when they believe an alleged offender was operating under the influence of a controlled substance. Unlike alcohol-related DWI offenses involving “per se” (Latin for “by itself”) violations when alleged offenders have blood or breath alcohol concentrations (BACs) of 0.08 or more, controlled substance-related DWIs have no per se limits.

Controlled Substances and DWI Defense Lawyer in Fort Worth, Arlington, Grapevine, Keller, and Southlake, TX

Were you or your loved one recently arrested for a controlled substance DWI in the greater Fort Worth area? You are not going to want to waste any time getting yourself, legal counsel.

The Law Offices of Richard C. McConathy regularly handle a wide variety of DWI cases, including offenses involving all kinds of controlled substances. Call (817) 422-5350 or contact us online to take advantage of a consultation.

Types of Controlled Substances and DWI Charges in Tarrant County

Texas Penal Code § 49.04 is the state DWI law and it applies to all drunk and drugged driving offenses. A controlled substance-related DWI offense will have the same criminal penalties as an alcohol-related DWI crime.

Common kinds of DWIs involving controlled substances include:


The major difference between a controlled substance DWI case and an alcohol-related violation usually concerns the testing that was performed on the alleged offender. Alcohol cases usually rely on breath samples taken from alleged offenders, but drug-related cases will typically involve blood or urine tests.

A major issue with these tests is that proof of a drug in a person’s system is not necessarily evidence that the drug was active at the time of an alleged offense. The Mayo Clinic notes that the average detection times for major controlled substances are as follows:


Drug Recognition Experts in Controlled Substances and DWI Cases

Drug Recognition Experts (DREs), police officers trained to identify drug-impaired drivers, are commonly involved in many controlled substance-related DWI arrests. A DRE is a commissioned Texas peace officer who has a minimum of two years of service and has completed Standardized Field Sobriety Tests (SFST) training as well as a reasonable DWI background and completion of a program involving pre-school, DRE school, and field certification.

A DRE will typically perform a 12-step battery of tests on a person suspected of being under the influence of a controlled substance. The process involves:

  • Breath Alcohol Test
  • Interview of the Arresting Officer
  • Preliminary Examination
  • Examination of the Eyes
  • Divided Attention Psychophysical Tests
  • Examination of Vital Signs
  • Dark Room Examinations
  • Examination for Muscle Tone
  • Examination for Injection Sites
  • Subject’s Statements and Other Observations
  • Opinions of the Evaluator
  • The Toxicological Examination

This process is inherently flawed since a DRE speaks to an arresting officer before they have even conducted many of the tests. The result is that the tests performed usually are subject to some confirmation bias.

Controlled Substances and DWI-main

Despite the requirements placed on DREs, they are rarely qualified to understand medical conditions. As a result, a person suffering from a complex medical condition could appear to be displaying symptoms of drug use when they are not, in fact, under the influence of any controlled substance.

Controlled Substances and DWI Defenses in Fort Worth

The first line of defense in many drugged driving cases concerns the accuracy of the testing. The simple truth remains that a person could test positive for a drug they actually took many days or weeks before their arrest.

Many of the other common defenses against alcohol-related DWI offenses also apply to controlled substance-related crimes as well. For example, the criminal charges could be completely dismissed if the police officer did not have a valid reason for the original traffic stop.

Fort Worth Controlled Substances and DWI Resources

10 myths about drugged driving | Texas District & County Attorneys Association (TDCAA) — View a TDCAA article discussing some of the most common myths surrounding drugged driving crimes. Learn more about when blood samples are taken and how they are tested. The article also discusses how easy it is to actually identify a drugged driver.

DrugFacts: Drugged Driving | National Institute on Drug Abuse (NIDA) — Visit this section of the NIDA website to learn more about why drugged driving is dangerous and how many people take drugs and drive. You can also learn more about which drugs are linked to drugged driving and how often drugged driving causes crashes. You can also find infographics relating to drugged driving on the NIDA website.

Find A Tarrant County Defense Attorney for Controlled Substances and DWI | Law Offices of Richard C. McConathy

If you or your loved one were arrested for a DWI involving a controlled substance in Fort Worth or a surrounding community in Tarrant County, you are going to want to quickly get yourself legal representation. Do not wait to contact the Law Offices of Richard C. McConathy.

Our firm can fight to possibly get your charges reduced or dismissed. We can provide an honest and thorough evaluation of your case as soon as you call (817) 422-5350 or contact us online to set up a consultation.

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