DWI Testing

If you were pulled over for suspected drinking and driving in Dallas, TX, chances are a police officer will ask you to step out of your vehicle to take a field sobriety test or blow on a breathalyzer machine to determine your breath alcohol concentration. Although you are not required to submit to alcohol testing in Texas, if you refuse, your driver’s license will automatically be suspended for at least. Additionally, if you are convicted of DWI in court, other court imposed penalties can result after a conviction for any driving while intoxicated (DWI or DUI) offense.

In Texas, many communities have implemented the “No Refusal Weekends.” If an individual is suspected of driving under the influence of alcohol or drugs, and the refuse to take a blood or breath alcohol concentration test (BAC), then the officer can act quickly to have a judge sign a warrant to take your blood by force.

This website is intended to provide you with general information about the testing process for DWI cases in Texas. In this article, you will find additional information about the following topics:

It’s important to note that only a consultation with an experienced attorney can provide you with deeper insight into your situation after a detailed analysis of the particular facts of your case.

Lawyer for DWI Testing in Dallas, TX

If you have been charged with a DWI offense after being chemically tested in Dallas, or any of the surrounding areas in Texas, including Garland, Irving, Grand Prairie, Irving, Denton, Plano, McKinney, Fort Worth, Arlington, Mesquite, Carrolton, Richardson, Lewisville or Frisco, contact Law Offices of Richard C. McConathy.

Attorney Richard McConathy is an experienced DWI lawyer who will make every effort to find defenses or mitigating factors to have your particular DWI charges reduced or dismissed.

Call Law Offices of Richard C. McConathy for a free consultation at (972) 233-5700 if your DUI arrest involved the use of chemical or field testing.

Dallas DWI Testing Information Center

Back to top

Implied Consent in Texas

According to Tex. Tansp. Code Ann. § 724.011, every individual who is arrested for any driving while intoxicated offense is considered to have given implied consent to testing of their breath or blood for any controlled substance, drug or alcohol.

Back to top

Texas DWI Field Sobriety Tests

Texas law enforcement officers typically first use a field sobriety test to determine alcohol impairment if they have pulled an individual over for DWI. There are standard tests law enforcement officers may use, including those described below.

A police officer may have you walk a certain amount of steps in a straight line, turn and repeat. The test requires you to walk heel to toe for the number of steps the officer tells you to take, and then take the same amount of steps back. The officer is typically looking for a person who cannot hold their balance, someone who falls, whether the individual uses their arms for balance, and if they are able to follow the instructions of the officer.

The officer may have you stand on one leg and count numbers out loud. The officer is testing your ability to do two tasks involving normal mental and physical abilities. During this test, the officer will determine if the suspect is capable of performing the task without stumbling, losing balance, hopping, putting the foot down, moving their arms, and/or incorrectly reciting the numbers.

The officer may move a pen or small light back and forth in front of the suspect’s eyes while their head is still. This test, also called the nystagmus test, is used to determine whether the individual’s eyes are able to follow the object without nystagmus, or involuntary jerking of the eyes. A failure of this test usually indicates a very high BAC. However, many people suffer from nystagmus without the consumption of alcohol.

The officer may also have a DWI suspect stand with their feet apart while they tilt their head backwards to test balance, or recite the alphabet backwards or a portion of the alphabet.

These tests do not conclusively show whether an individual is intoxicated or not. The results of a field sobriety test are completely based on the officer’s opinion. Someone can “fail” a field sobriety test for a variety of reasons, including if the person is uncoordinated or they naturally have nystagmus of the eyes. The closest method to determining whether an individual has consumed alcohol is through a breath or blood chemical test, but even those are not completely accurate.

Back to top

DWI Breath Tests in Texas

An individual suspected of DWI may also be requested to submit to a breath test to determine their alcohol concentration level. If they consent and blow over the legal limits of .08, they will automatically be arrested for DWI under Texas’ per se DWI law. However, they can also be arrested if the law enforcement officer believes their normal mental and physical faculties are impaired from the use of alcohol or drugs.

According to Tex. Transp. Code § 724.016, an arrested DWI offender’s breath specimen is permitted to be taken by a peace officer and analyzed by a qualified individual.

If an individual takes a breath test and blows over the legal limit, the results of the test may be challenged in court. The results of the Intoxilyzer 5000, or breath test machine, can sometimes be inaccurate or unreliable. For example, someone’s alcohol concentration level can be increased if the machine is not properly calibrated, if the person administering the test made a mistake, and/or if the suspect has a substance similar to ethanol in their mouth from toothpaste or mouthwash.

Back to top

Dallas DWI Blood Testing

When an individual is arrested for DWI in Dallas, the arresting officer may take the alleged offender’s blood sample to test for alcohol concentration levels. Blood alcohol concentration (BAC) is usually tested through a process called gas chromatography. This method compares the individual’s blood sample against a control sample.

According Tex. Transp. Code Ann. § 724.017, only certain people may take a DWI suspect’s blood when requested by a peace officer.

Inaccuracies may also arise when an individual’s blood is tested for alcohol concentration levels. For example, if a person not authorized to take the blood did so, the results of the blood test may be thrown out in court. Also, samples taken in a hospital after the individual was involved in a car accident are taken from the blood serum and not the whole blood, which is often a less accurate measurement.

Back to top

Administrative License Suspension in Dallas

If an individual refuses to submit to chemical testing in Dallas for a DWI, their license will automatically be revoked. This is not a criminal penalty for a DWI, but a civil penalty. If the individual is subsequently convicted of a DWI in Dallas, they may also have their license suspended then as a part of a criminal penalty.

After the individual receives notice of a suspension, they can request a hearing, submitted in writing within 15 days of notice of the suspension, by the Office of Administrative Hearings to determine if the license suspension was justified.

According to Tex. Transp. Code § 724.035, the period of suspension is 180 days for a first DWI refusal. If any individual has one or more alcohol-related driving charges on their driving record within the preceding years, a refusal will result in a two year license suspension.

Back to top

Resources for Driving While Intoxicated (DWI) Testing in Texas

Texas Constitution and Statutes – This link is to chapter 724 of the Texas Transportation Code, which defines implied consent and chemical DWI testing in Texas and the potential penalties for a testing refusal.

Texas Breath Alcohol Testing Program Requirements – This link is to the operator’s manual of the Texas breath alcohol testing program. The manual contains information about how breath tests in Texas are supposed to be administered, information about alcohol concentration levels, invalid tests, ethanol information and detailed information about the Intoxilyzer 5000.

Texas Alcoholic Beverage Commission – The Texas Alcoholic Beverage Commission (TABC) is a state agency that regulates the alcoholic beverage industry throughout Texas. This link provides access to information about Texas’ DWI laws, signs of intoxication and miscellaneous alcohol consumption information. A local field office is located at:

2225 East Randol Mill Road, Suite 200
Arlington, Texas 76011
Phone: (817) 652-5912

Back to top

Finding an Attorney for DUI Testing in Dallas Fort Worth, TX

Contact Law Offices of Richard C. McConathy today for a consultation about your failed DWI sobriety test throughout Dallas County in Texas. Richard McConathy is a knowledgeable attorney in Dallas for DWI who will make every effort to help you achieve the best possible outcome for your alleged DWI offense.

Call (972) 233-5700 for a consultation about your DWI charges throughout Dallas County in Texas and the surrounding counties of Denton County, Collin County, and Tarrant County.

Back to top

Client Testimonials

Read More Stories
(972) 233-5700
  1. videosVideos
  2. phone
  3. case resultsResults
  4. contactContact