Breath testing devices used by police in the Dallas Texas area can be inaccurate because of the assumptions that all people metabolize alcohol at the same rate, ate the same amount of food, have the same metabolisms; and drank the same amount of alcohol.

A portable breath test device (“PBT”), is not a breath test like an intoxilyzer 5000.  It is very small and used by police officers at the scene of the arrest.  The PBT is not approved by Texas Department of Public Safety for use in criminal prosecutions or in administrative license revocation proceedings.  Also, Texas will not allow the results of a PBT to be admissible in court.

Texas courts will allow the results of the intoxilyzer 5000 machine if the results are proved up properly by the Prosecutor in court.  Therefore, our Dallas DWI lawyer, Murray L. Bristol, requests all the maintenance records regarding the specific Intoxilyzer 5000 machine that his client blew into.  This allows him to research the records of the breath test machine to determine if it had errors during the 30 days before and after the breath sample date of his clients and therefore was not working properly.  He further uses the following defenses in breath tests as well.

The Validity Of Breath Testing Rests On Assumptions That Can Be Attacked By An Experienced DWI Attorney In A Wide Variety Of Cases:

  1. The Machine Is In Proper Working Order And Has Been Properly Calibrated. Even if everything is in proper working condition, there can be an acceptable variation of +/- .02. If your result is a .10% that’s a 20% error factor. How would you feel if the altimeter of an airplane was 20% off?
  2. The Sample Was Properly Obtained. The law requires that you be under continuous observation for 15 minutes prior to your breath test to prevent “MOUTH ALCOHOL.” If the operator of the breath machine did not have you under continuous observation for 15 minutes prior to testing, your test may be invalid. Even if you were observed, you may have medical conditions, which make you an improper candidate for breath testing. These conditions include common ailments such as heartburn and gum disease.
  3. The Sample Was Obtained After You Absorbed All The Alcohol. Breath testing assumes that the subject is post absorptive. This is important because the machine is calibrated to multiply the breath result by 2100 to calculate your blood alcohol level. If you were still absorbing alcohol, this would tend to significantly over report your true blood levels.
  4. The Temperature Of Your Breath Was 34 Degrees Centigrade . This is an assumption that is made in every breath test in Texas. State of the art breath testing equipment actually measures the temperature of your breath and will subtract any false high result due to elevated breath temperature. Studies done with this equipment establishes that the real average breath temperature for arrestees in DWI cases is closer to 35.5 with readings actually over 37. This alone would cause a false high of between 10-20%.

Common Challenges To Breath Tests:

  1. The Machine Was Not Properly Operated
  2. The Machine Was Not Properly Maintained
  3. The Machine Was Not Properly Calibrated
  4. The Machine Was Affected By Radio Frequency Interference (Police Radio etc.)
  5. The Machine Has An “Acceptable” Range Of +/- .02%
  6. Your Body Temperature Was Greater Than 98.6
  7. You Were Tested Within 2 Hours From Your Last Drink
  8. You Have Medical Or Dental Problems That Make You An Improper Candidate For Breath Testing
  9. The Officer Did Not Have You Under Continuous Observation For 15 Minutes Prior To Giving You The Breath Test
  10. Your Symptoms And Drinking Pattern Are Inconsistent With The Test Result
  11. Manufacturer does not warrant that the Intoxilyzer is fit for any particular purpose
  12. Intoxilyzer is capable of breath preservation, however, DPS purposely fails to require the breath specimens to be saved, therefore, no independent testing can be done
  13. Residual alcohol in the mouth increased the results

To speak to our aggressive Dallas DWI lawyer, Murray L. Bristol, please call our office at (214) 880-9988, contact him through the form on this website, and he will contact you promptly for a free consultation.