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DWI Breath & Blood Testing in Plano

Protecting Clients in Collin, Dallas & Tarrant Counties

Blood and breath testing is a very complicated aspect of DWI. It takes dedication and education to fully comprehend how these processes work. By understanding these testing procedures, we also know how inaccurate and unreliable they can be. If you have been arrested for DWI in Plano or Dallas Counties, getting the help of an experienced criminal defense lawyer can make a major difference in your life.

Dial (214) 855-7737 now or contact us online to schedule your free initial consultation.

The following are the most common questions we have been asked concerning these tests. At the Wilder Law Firm, our knowledge in this area of DWI litigation is often the difference between a conviction and being found Not Guilty.

  • How accurate are Texas chemical testing procedures?

    Texas law provides that DWI suspects can have their alcohol concentration tested either by a urine, blood, or breath test. Urine testing is the least accurate and is rarely ever performed. In the scientific community, it is considered to be the least reliable method of testing.

    Blood testing is thought of by the majority of the scientific community to be the most reliable and accurate method of determining a person’s alcohol concentration. Although this is the least desirable method for the police due to its inconvenience, blood testing allows the arrested person to have his or her own expert re-test the blood sample for accuracy.

    Breath testing is the most convenient method for the police. However, the reliability and accuracy of breath testing is continually debated in the scientific community. In addition, breath samples are not preserved for a subsequent test to check the first test’s reliability and accuracy. Therefore, it is impossible to use subsequent testing to prove that the breath test was faulty, which could result in an innocent person being unjustly convicted. The state of Texas could save each breath sample for less than $2.00, but they choose not to do so!

    In short, the police like to use the cheapest, most convenient, non-preserved, scientifically-debated chemical test when your freedom is on the line!

  • How is breath testing done in Texas?

    The State of Texas uses a machine called the Intoxilyzer 5000, which is commonly referred to as the “breathalyzer.” The Intoxilyzer 5000 (I called it the Intoxicator or Intoxiliar because of its inaccuracies) costs about $7,500 and can last as long as 10 years.

    It works on the theory of infrared spectroscopy where compounds absorb different light frequencies (wavelengths). A light bulb positioned at one end of a cylinder sends light through filter wheels in the cylinder to a receiver on the other side. Alcohol will absorb certain wavelengths of light, allowing the machine to detect wavelengths of light absorbed by alcohol.

    The machine must convert the reading to an amount great enough for us to understand. The difference in light emitted and received is computed through a computer program in the machine to come up a value that can be compared to a .08. The conversion the machine makes on the differences in light would be the equivalent of taking the paper towel tube and increasing its size to that of a 55 gallon drum. Any error would then be exaggerated by that amount.

  • How reliable is the breath test?

    Neither DPS (Department of Public Safety) nor the manufacturer of the machine will allow anyone other than law enforcement to test the machine for its accuracy and reliability. The manufacturer does not warrant the intoxilyzer for any particular purpose. The machine is not warranted for accurate and reliable breath testing.

    Proponents of the intoxilyzer state that the machine will only read light absorbed by alcohol, while opponents state the machine often misreads other substances in the breath, thus giving an inaccurate reading. Normally, a procedure is only acceptable when open and available for the scientific community to test and retest, yet this is not permitted with the intoxilyzer. What are they trying to hide?

    The intoxilyzer is capable of preserving breath samples at a cost of less than $2.00, but DPS purposefully discards samples even when they could exonerate innocent people from sentencing. Further, re-testing of the breath sample could be done by a more accurate process known as gas chromatography, but they do not.

    The intoxilyzer also assumes that everyone has a blood/breath ratio of 2100 parts of alcohol per 1 part of alcohol in the breath. A person with a lower blood/breath ratio will be adversely affected because the intoxilyzer will erroneously read too high, thus a person who should test at .05 or .06 could actually test well above a .10. Scientists have even documented people with blood/breath ratios as low as 1100/1.

    Because the temperature of your body can affect what the intoxilyzer reads, a person with a fever will also have a higher breath test reading than normal even though your body temperature has nothing to do with the amount of alcohol you have consumed.

    The bottom line is this device is fast and cheap. If a person passes a breath test, some police agencies will release them without filing any charges. It is much easier to do this than file a DWI, request a blood test, and later have to explain why they arrested a person whose blood test came back under the legal limit.

  • Should I agree to take a chemical test in Texas? What happens if I don’t?

    If you do not want to take the test or are unsure to do so, ask the officer for permission to call a lawyer before you make your decision. They will not likely give you the opportunity. Our firm has only seen one police officer honor this request. This is when the debate begins.

    You have not refused to take the test, but you must be polite and courteous as you stand firm with your request to talk to a lawyer before deciding whether to take a test. The officer will repeat that you are not entitled to a lawyer at this point in time, and that the decision is yours and yours alone. Just keep requesting to speak to a lawyer.

    The officer will eventually tell you that if you do not agree to take the test, he will consider your actions to constitute a refusal. That is his job, but you will have set the stage for a jury trial.

    This is because:

    • The prosecutor cannot argue that you refused the test because you knew you would fail
    • Many, if not most, jurors sympathize with those who make this request

    If you refuse to take the chemical test, you will be charged with DWI, but even if you pass the chemical test, you could still be charged with DWI. You were arrested because the officer determined you had lost control of your physical faculties and/or mental faculties when he stopped you. At this point, the officer did not know what alcohol level was in your body.

    If you pass a breath test, you will not lose your license. If you refuse, you will likely have to schedule an ALR (Administrative License Revocation) hearing where you may or may not lose your driver’s license. It is important to request an ALR hearing.

  • In Texas, can I choose to have a blood test rather than a breath test?

    Texas law lets the officer choose which test to offer. If the officer asks you to take a breath test, and you say that you will only take a blood test but they refuse, they will count your blood test request as a breath test refusal. The officer will then confiscate your driver’s license, and your license will be subject to suspension. However, if this happens, the officer does not look fair in not giving you a blood test. Simply put, a blood test requires more work for the officer.

    Section 724.019 of the Transportation Code states:

    • A person who submits to the taking of a specimen of breath, blood, urine, or another bodily substance at the request or order of a peace officer may, on request and within a reasonable time not to exceed two hours after the arrest, have a physician, qualified technician, chemist, or registered professional nurse selected by the person take for analysis an additional specimen of the person’s blood.
    • The person shall be allowed a reasonable opportunity to contact a person specified by the subsection above.
    • A peace officer or law enforcement agency is not required to transport for testing a person who requests that a blood specimen be taken under this section.
    • The failure or inability to obtain an additional specimen or analysis under this section does not preclude the admission of evidence relating to the analysis of the specimen taken at the request or order of the peace officer.
    • A peace officer, another person acting for or on behalf of the state, or a law enforcement agency is not liable for damages arising from a person’s request to have a blood specimen taken.

    Do you find it interesting that the State of Texas has so much “confidence” in the breath machine that they give you the right to an independent blood test?

    Do you find it interesting that the law does not require the officer to inform you of this right?

    One officer even testified in front of a jury that he did not have to tell the arrested person of their right to an independent blood test. He further testified that my client could have read the transportation code and found out about this right.

    Would you trust this officer’s opinion? The jury did not either. The verdict? Not Guilty.

    These shortcomings are not meant to be exhaustive. But this illustrates the need to hire a qualified attorney who is knowledgeable in all aspects of DWI law.

  • May a Texas police officer force me to take a breath or blood test?

    The police can never compel a breath test. An officer can compel a blood test only if there has been an accident where serious bodily injury, potential fatality, or death has occurred and the arrested person refused the test.

  • Does a person have the option not to take a breath or blood test?

    Yes. Even though Texas has the implied consent law, a person arrested for DWI may refuse the test requested.

    This refusal can result in the following penalties:

    • 180-day suspension of your driving privilege if this is your first DWI arrest.
    • 2-year suspension of your driving privileges for a subsequent arrest within 10 years if you refused to submit to a test in your first arrest.
    • The prosecutor can admit your refusal into evidence in your DWI trial. The prosecutor will then argue that you refused the test because you knew you were intoxicated and that you would fail the test.

    If you submit to a test and fail, your driving privileges can be suspended and the following penalties may occur:

    • 90-day suspension of your driving privilege if your driving record shows no prior alcohol-related arrests
    • 1-year suspension of your driving privilege if you have a prior conviction or suspension with the preceding 10 years
    • The prosecutor can admit the results of the test into evidence at your DWI trial

    If you do not want to take a test, it is better to tell the officer that you want to talk to a lawyer before making the decision, as opposed to just refusing. Again, they most likely will not give you the opportunity to talk to a lawyer, but no test will be given.

  • Should my Texas lawyer have any specific Field Sobriety Test training?

    Any lawyer you hire should be able to answer your DWI questions and have completed both the NHTSA approved Field Sobriety Test Student Course to be a practitioner and the NHTSA approved Field Sobriety Test Instructors Course to be an Instructor. Valuable knowledge on how to properly cross examine an officer is gained when the lawyer is trained exactly how an officer has been. If a lawyer is not dedicated enough to obtain this intensive training, do you think they really have your best interest at heart when representing you?

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