Breath Testing in Texas: Indefensible Evidence or Junk Science? by Plano DWI attorney Troy Burleson

By Collin, Dallas and Denton County DWI Lawyer Troy Burleson

One of the most debated pieces of evidence in Texas DWI trial is breath test evidence. Generally, most defendants who give a breath sample over the Texas legal limit of 0.08 either plea guilty or are told not to fight the case by their legal counsel. If you have been charged with a Texas DWI and you gave a breath sample over the legal limit, you situation may not be hopeless.

Most good DWI attorneys will counsel their clients that the breath test machine used in the state of Texas is not without flaws. A good DWI attorney who properly educates the jury on these flaws gives his or her client a fighting chance to get a verdict of not guilty.

Most people, including those who are attorneys, reading this entry may be shaking their heads saying that there is no way to beat a government machine in trial. To those who doubt that a breath test DWI trial cannot be won, I would ask the following questions:

  1. Who do you think manufactures the breath testing machine used in Texas?
  2. How does it work?
  3. Is the machine warranted by the manufactures to give valid breath-alcohol concentration result for human subjects?
  4. Has the entire machine been held scientifically valid for providing breath-alcohol scores?
  5. How much does an inch weigh?
  6. What does a valid breath test score mean?
  7. What assumptions did the manufacturer of the breath test machine have to make and are therefore built into the machine?
  8. What is RFI?
  9. Can an operator of the breath test machine cause an erroneous test result?
  10. Does the machine have a margin of error, and if so, what is that margin?

These are only a few examples of questions that can be asked at trial to show the jury that the breath test machine is not above questioning. Must jurors, before they are educated by a proper voir dire, assume that the breath machine is made by the government and has no internal, mechanical flaws. This is simply not the case. Keep in mind, as I have reported here before, that the NUMER TWO cause of wrongful convictions is lab error and JUNK SCIENCE.

For years, the government used lie detector tests as scientific evidence about a person’s guilt. These machines have since been ruled inadmissible for the purposes of establishing guilt. Who’s to say that one day, these breath test machines will not be discarded, like lie detectors, for trial purposes.

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