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DUI, DWI Tests

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. The following are the most common questions we have been asked concerning these tests. The lawyer's knowledge in this area of DWI litigation is often the difference between a conviction versus being found Not Guilty.

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Breath & Blood Testing

How accurate are the 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!

Return to the questions.

How is Breath Testing done?

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 Spectrosphopy, which is the absorption of infrared light. Different compounds will absorb different frequencies (wavelengths) of light. The machine has a light bulb positioned at one end of a cylinder. There are filter wheels in the cylinder, and on the other side of the filter wheels is a light receiver. Alcohol is supposed to absorb certain wavelengths of light and the machine is supposed to only detect wavelengths of light absorbed by alcohol.

The machine shines a light through the cylinder and the filter wheels will be turning. The filter wheels are designed to filter out potential contaminants. The breath sample enters the cylinder and passes through the filter wheel. The amount of light received at the other end of the cylinder is then recorded. The difference in the starting and ending amounts of light is the result. Interesting enough, the amount of light that is absorbed is not alcohol specific!

The amount of the breath sample and any reading of alcohol are very minute. The machine must make a multiplication conversion 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.

Return to the questions.

How reliable is the Breath Test?

There is much debate on the intoxicator; I mean the intoxiliar; I mean the intoxilyzer. Proponents of it state that the machine will only read light absorbed by alcohol, while opponents state the machine often misreads other commonly found substances in the breath as alcohol, thus giving an inaccurate high reading.

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. It is generally understood that for a procedure to be accepted as accurate and reliable in science, it must be open and available for the scientific community to test and retest the procedure. This is not permitted with the intoxilyzer. What are they trying to hide?

The manufacturer does not warrant the intoxilyzer for any particular purpose. The machine is not warranted for accurate and reliable breath testing. Would you buy a car without a warranty?

The intoxilyzer is capable of preserving breath samples, but DPS purposefully fails to preserve these samples. The cost of preserving breath samples would be less than $2.00, and would allow arrested persons the opportunity to have their breath sample checked for accuracy. If found to be inaccurate, it could prevent an innocent person from being unjustly convicted. Further, re-testing of the breath sample could be done by a process know as gas chromatography, which is considered to be a more accurate and reliable method of testing breath samples for alcohol than the intoxilyzer. Why do they not preserve samples when your freedom is on the line?

The intoxilyzer also assumes that everyone tested will have a blood/breath ration of 2100/1 (i.e. 2100 parts of alcohol in the blood for every 1 part of alcohol in the breath). If a person has a higher blood/breath ratio (i.e. 2400/1), the test will not be adversely affected by this assumption. However 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. Additionally, scientists have documented people with blood/breath ratios as low as 1100/1. Do you want to take the risk that the intoxilyzer may falsely hurt you, which could result in a conviction that will be on your record?

A person with a fever will have a higher Breath Test reading than an identical person without a fever. Therefore, the temperature of your body can affect what the intoxilyzer reads, and your body temperature has nothing to do with the amount of alcohol you have or have not consumed.

The experts continue to testify that the intoxilyzer was "functioning properly and capable of giving accurate results." This sounds good, but what do they mean by capable? (If I buy a ticket, I too am capable of winning the lottery…)
The bottom line is that the intoxicator/intoxiliar/intoxilyzer is fast and cheap. Further, if a person passes a Breath Test, some police agencies will release the individual arrested and not file 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.

This is not an all-inclusive list, but it is obvious that there are many problems with the machine.

Return to the questions.

Should I agree to take a chemical test? What happens if I don't?

If you do not want to take the test, or are unsure whether to take it or not, ask the officer for permission to call a lawyer before you make your decision. They most likely will not give you the opportunity. I have only had 1 police officer who has ever honored this request.

Being that the officer will not give you this opportunity, the debate will begin. You have not refused to take the test. You need to be polite and courteous and just stand firm with your request to talk to a lawyer before deciding whether to, or not to, take a test. The officer will continue to tell you 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. First of all, the prosecutor cannot argue that you refused to take the test because you knew you would fail. Secondly, the majority of jurors I have spoken with have sympathized with my clients who have made this request. Jurors have told me that if they were arrested, they would want the opportunity to talk with a lawyer too.

The reality is that even if you pass the chemical test, you could still be charged with DWI. You were arrested because the officer formed the opinion that you had lost the normal use of your physical faculties and/or mental faculties when he stopped you. At this point, the officer did not know what, if any, the alcohol level was in your body. Even if you pass the chemical test, the officer can still charge you with DWI. However, if you pass the test, you will not lose your driver's license.

If you fail the test, you will be charged with DWI. Depending upon the outcome of the ALR (Administrative License Revocation) hearing, you may or may not lose your driver's license. If you fail, the officer shall immediately take your driver's license from you and issue you a temporary driving permit. It is important to request an ALR hearing.

If you refuse to take the chemical test, you will be charged with DWI. The officer already formed the opinion that you had lost the normal use of your physical faculties and/or mental faculties when he or she stopped you. If you refuse, the officer will immediately confiscate your driver's license and issue you a temporary driving permit. Again, depending upon the outcome of the ALR (Administrative License Revocation) hearing, you may or may not lose your driver's license.

Finally, most police officers I know would not take a Breath Test.

Return to the questions.

Can I choose to have a blood test rather than a Breath Test?

Texas law gives the officer the choice of 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 and they do not give you the opportunity to take a Blood Test, 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. (Why would the officer work harder if they do not have to?)

Section 724.019 of the Transportation Code states:

(a) 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.

(b) The person shall be allowed a reasonable opportunity to contact a person specified by Subsection (a).

(c) 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.

(d) 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.

(e) 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?

I actually had an officer testify 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!

Now I ask you, 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.

Return to the questions.

May a 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.

Return to the questions.

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:

  1. a 180-day suspension of your driving privilege if this is your first DWI arrest,
  2. a 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, and
  3. 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:

  1. a 90-day suspension of your driving privilege if your driving record shows no prior alcohol related arrests,
  2. a 1-year suspension of your driving privilege if you have a prior conviction or suspension with the preceding 10 years, and
  3. 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.

Return to the questions.

Do they 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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Our DUI/DWI criminal defense attorneys have a proven record of winning the most difficult cases. In addition to their superior litigation skills, our attorneys have undergone extensive training in the administration of Field Sobriety and Intoxilyzer Tests.

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