Impaired Versus Intoxicated in Texas

In Texas, prosecutors take driving while intoxicated seriously. But what does it mean for a driver to be “impaired?” Texas law doesn't specifically address “impaired” drivers, but it does define intoxication. While many people use the terms impaired and intoxicated interchangeably, it's important to understand the difference between the terms and how they apply to adults and those under 21 years of age.

Driving While Intoxicated

In Texas, someone is “driving while intoxicated” if they are intoxicated while driving a motor vehicle in a public place. See Tex. Penal Code § 49.04 (2011). The Texas Penal Code defines “intoxicated” as:

  • 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.

Tex. Penal Code § 49.01 (2) (2001). So, the police can show that a driver is intoxicated in two ways.

  1. Normal Use of Faculties

Showing that a driver doesn't have the normal use of their mental or physical faculties typically happens through careful observation and questioning from the police and field sobriety tests. The standard field sobriety test is a series of three evaluations:

The horizontal gaze nystagmus (HGN)

When the eye looks to the side, it involuntarily jerks. When a person has been drinking, the nystagmus reaction is supposed to be more exaggerated. For the test, the police officer will have you follow an object back and forth with your eyes. They will watch for whether you follow the object smoothly with your eyes, involuntary eye-jerking when looking to the side, and where the nystagmus reaction happens. This test is a medical evaluation given by police officers who don't ask the medical questions that should accompany the HGN test.

Walk and turn

The walk and turn evaluated your ability to “walk a line” and follow directions with your attention divided. The officer will watch for your ability to follow directions, your balance, whether you take the correct number of steps, failing to touch heel to toe while walking, and several other “signs” that you may be impaired. It's very easy for environmental conditions or your health conditions to impact the results of this test.

The one-leg stand

For this test, you have to stand on one leg, with one foot 6 inches off the ground for 30 seconds. The officers are watching for whether you use your arms to balance, any swaying, any hopping, and whether you put your foot down. Again, any physical health condition you have, and environmental factors can easily affect this test's results. Some people can't perform this even while fully sober.

After performing a field sobriety test, police can arrest you for driving while intoxicated based on their conclusion that you don't have the normal use of your mental or physical faculties. The sobriety test is a judgment call made by the arresting officer and can be challenged in court more easily than a test measuring your BAC.

  1. Blood Alcohol Concentration

Once you are under arrest, the police will ask you to take a blood or breath test. BAC is the second way the police can prove intoxication in a driver.

Breathalyzer test

The breathalyzer test usually happens about 45 minutes after the police stopped you, and you will blow into an intoxilyzer. However, the police have to prove that you were intoxicated while driving. The legal BAC limit in Texas is .08% or .04% for a commercial driver's license. Unfortunately, breathalyzer tests can be unreliable. They don't measure the alcohol concentration in the blood or brain. Rather a breath test measures the evaporated alcohol that travels out of the body via the airway. An experienced DWI attorney will know and understand how to challenge these results in court.

Blood test

The police can also ask you to take a blood test. However, this test involves a qualified person drawing your blood at the police station, hospital, or another location and then testing it with gas chromatography. There are some situations where the police can make you take a blood test:

  • They get a warrant because you refused an earlier request for a blood or breath test;
  • You were in an accident, and someone died or was seriously injured, and the police reasonably suspect that you were driving while intoxicated;
  • You were driving with a child in the car, and the police reasonably suspect you of DWI; or
  • A court convicted you of any two previous DWI cases, DWI with a child passenger, intoxication assault, or intoxication manslaughter.

While blood tests are far more accurate than breath tests, there can still be problems with the calibrated equipment, the chain of custody of the blood samples, and lab errors. Again, an experienced DWI attorney will know how to challenge these results.

Driving While Impaired

While many people use the term “impaired” interchangeably with “intoxicated,” they don't mean the same thing. To be legally intoxicated in Texas, you must have a BAC of .08% or not have the normal use of your mental and physical faculties because of alcohol or drugs. We typically refer to drivers with some amount of detectable alcohol in the body, but under the .08% legal limit, as “impaired.” Driving while impaired isn't necessarily illegal for adults in Texas. However, for drivers under the age of 21, driving with any detectable amount of alcohol in the body is illegal. Thus, driving while impaired is illegal for drivers under 21.

Driving under the influence of alcohol (“DUI” or “DUIA”) is a charge reserved for those under the legal drinking age. It is illegal for anyone under the age of 21 to buy, attempt to buy, or consume alcohol. As a result, it is illegal for anyone under 21 to drive with “any detectable amount of alcohol” in their system. Tex. Alcohol  (2009). Police officers will use the same field sobriety tests and blood and breath tests on drivers under 21. However, even if the driver is not legally intoxicated, police can arrest them if impaired by using any amount of alcohol or drugs.

If you or your child face a DWI or DUI charge, you need to consult a skilled and experienced DWI defense attorney right away. Attorney Doug Murphy is Board Certified in DWI defense law. He is one of only two Texas attorneys with board certifications in both DWI and criminal defense law from the Texas Board of Legal Specialization. Doug is also a noted expert in DWI defense law, and attorneys nationwide seek his expertise. Best Lawyers in America also recently named Doug the “Lawyer of the Year” for 2021 in DWI defense based on the peer reviews of fellow Houston-area attorneys.

Whether police arrested you while allegedly intoxicated or impaired, you have legal options. Contact our office today. A DWI can impact many areas of your life, but we can help.

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