Breathalyzer Calibration and DUI Cases


During a traffic stop, if a law enforcement officer suspects that you have been drinking, he or she may request that you submit to a breath test to measure your blood alcohol content (BAC). Such tests are performed by using Breathalyzers, a portable device that measures the amount of alcohol in breath when an individual blows into the device. Though Breathalyzer results are commonly accepted as evidence of BAC in DUI cases, the results can be inaccurate for many reasons (such as breathalyzer calibration) and therefore the circumstances surrounding the breath test should be carefully examined for errors.

Breathalyzer Calibration and other requirements

In order for results of a particular Breathalyzer device to be admissible, the following general guidelines must be met:

  • The device must be made by an acceptable manufacturer;
  • The device must have been regularly inspected and tested for accuracy;
  • The device must be routinely calibrated;
  • The device must provide two test readings within 0.02 percent of each other;
  • The law enforcement officer must be certified to use that particular Breathalyzer device and must use the device as he was trained to do; and
  • The law enforcement officer must ensure the suspect does not smoke, vomit, burp, or eat in the time preceding the test.

If the device is not properly maintained and calibrated or if the officer performs the breath test in an incorrect manner, the test results should be challenged by your DUI defense attorney and should not be accepted by the court. Showing that the device was not calibrated correctly often requires a subpoena of the records of the law enforcement agency regarding the maintenance of the particular device used in your case. If the records are inadequate, out of date, or incomplete, they may be used as evidence of improper calibration and inaccurate BAC results.

BAC test results are often the main piece of concrete evidence that a prosecutor may have in a DUI case. Once the test results are questioned or proven inaccurate, the burden then falls on the prosecution to present other types of evidence of your intoxication. Such evidence, including physical signs of intoxication or performance on field sobriety tests, is often significantly more subjective than numerical BAC results. The prosecution then often depends upon the recollections of the arresting officer, which can be challenged in court as the officer testifies by the defense attorney. For this reason and more, investigating breath test results can be very effective in a DUI case.

How an experienced Denver DUI defense attorney can help

If you underwent a breath test and believe the results are inaccurate and that you were wrongfully arrested and/or charged for DUI, an experienced DUI defense lawyer will have the resources necessary to investigate the circumstances surrounding your breath test to identify any errors that were made. You should always have the assistance of an attorney who understands the technology behind Breathalyzers, the need for routine maintenance and calibration, and the common mistake made by law enforcement agencies in regard to breath tests. If you are facing DUI charges, please do not hesitate to call 303-DUI-5280 to schedule a free consultation with the Tiftickjian Law Firm today.

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