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Atlanta Criminal Defense Lawyers > Blog > DUI > Are Breathalyzers Accurate?

Are Breathalyzers Accurate?

Anyone who has been arrested under the suspicion of driving under the influence may be asked to submit to a breathalyzer test. Some may have read about these tests and be hesitant to take one. If a person blows over the legal limit, they have given the police proof that they are intoxicated. Or have they? While the average driver may assume that breathalyzer results are cut and dry, experienced attorneys know the truth.

How Breathalyzer Tests Work

When you are asked to submit to a breathalyzer, you are being asked to have the alcohol vapor in your body measured. The vapor exits through your breath, and the machine measures alcohol vapor as you blow into the mouthpiece.

Breathalyzer Errors

There are several types of breathalyzer machines on the market used by police. The machine a police department chooses to use depends on many factors, including the department’s budget. No matter which machine is chosen, it is susceptible to error. Some of the most common errors occur because of:

  • The margin of error within the device itself
  • Partition ratio – the physiological differences among all drivers
  • RFI or radio frequency interference
  • Improperly calibrating the device
  • Alcohol in the person’s mouth
  • Anything that may taint the sample of breath

There is a margin of error within any breath-test machine. For some breathalyzers, that margin is .01 percent. The ticket printed from the machine may have a certain number and a +/- .01. This tells an officer, and subsequently a judge, that if you registered a .08, you may actually have a concentration of .07 or .09.

A partition ratio exists among adults. Many factors come into play that affect a person’s partition ratio. Gender, size, breathing patterns and even body temperature affect these ratios. Other factors, such as diabetes or acid reflux, can also skew the results.

RFI can alter a test. The electronic waves that are emitted from an officer’s radio can interfere with the test. If RFI is detected, the test is invalid and must be readministered.

Calibration may be done incorrectly. A breathalyzer must be calibrated regularly. Typically, it is something that needs to be done on a regularly scheduled basis. States dictate how often this needs to happen. In many states, it is every 10 days or 150 tests.

Alcohol in the mouth can skew the results. If a person vomits or burps just before taking the test, there may be alcohol present in the mouth. In some cases, using a vaping device can also increase the breathalyzer reading, thanks to the ingredients in the liquids. This is why people are supposed to be observed for about 20 minutes prior to the administration of the test.

If you have been arrested for driving under the influence in DeKalb County and submitted to a breath test, you are not automatically guilty. Call our team of experienced DUI attorneys today for assistance. We know how to defend those charged with DUI, even if they have submitted to testing. Your case is not hopeless. Call today and schedule your free case evaluation.

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