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Breath Test

“Intoxicated” means not having the normal use of your mental or physical faculties by reason of the introduction of alcohol, a controlled substance, a drug, a dangerous drug, a combination of two or more of those substances, or any other substance into the body; or having an alcohol concentration of 0.08 or more. After you are arrested for DWI or other alcohol related offense, the arresting officer will ask you to submit to either a blood, breath or urine alcohol test.

If you agree to submit to a breath test it will be conducted at the county jail. Law enforcement officers use a machine called an intoxilyzer to conduct the breath test. Texas primarily uses the Intoxilyzer 5000 EN model.

How does it work?
The intoxilyzer (sometimes incorrectly referred to as the breathalyzer) utilizes spectroscopy to measure the alcohol concentration in your breath. Essentially, it measures the amount of light absorbed in your breath specimen. The higher the concentration of alcohol in the specimen, the more light is absorbed.  The less the amount of light that makes it to the sensor, the higher the readout will be for an alcohol concentration.

How is it given?
When you blow air into the mouthpiece, the air goes through a tube and into the main chamber of the intoxilyzer. Light is then shone into the chamber where it is absorbed into the breath specimen. The more light absorbed into the specimen the higher the alcohol concentration. Once the intoxilyzer analyzes the light absorption the machine calculates the number into an alcoholic concentration value.

Is the breathalyzer accurate?
The government relies on the results of the breathalyzer to prosecute citizens for DWI. The machine, however, is not accurate for a variety of reasons and is not consistently trustworthy.  Potential problems associated with the intoxilyer include, but are not limited to the following:

  • The intoxilyzer is rarely checked for accuracy.
  • The intoxilyzer is rarely checked for proper function.
  • The intoxilyzer has a rate of error of 0.02.
  • The intoxilyzer is not warranted to read accurately by the manufacturer.
  • The intoxilyzer can be contaminated by a prior user.
  • The intoxilyzer test results may be affected if the user has a fever.
  • The intoxilyzer test results may be affected by other substances in your body.
  • The intoxilyzer is not required by the state to perform perfectly.
  • The intoxilyzer is self-testing.
  • The intoxilyzer assumes all testers will have the same blood/breath ratio.
  • The intoxilyzer can be affected by mouth alcohol.
  • The intoxilyzer can be affected by GERD.

Contact Doug Atkinson to discuss the defenses available in your case relating to the intoxilyzer in your DWI case.

Can you refuse to take a breath alcohol test?
Texas has an implied consent law which means that if you applied for and received a Texas driver’s license you agreed to take a breath or blood alcohol test if arrested for DWI or other alcohol related offense. However, you can refuse to take the test.

There are consequences to refusing to take the test. The government’s attorney can use your refusal against you during your trial. Further, DPS may suspend your driver’s license longer than if you had taken the test.

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