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How Accurate Is a Breathalyzer Test During an OWI Traffic Stop?

Posted on in DUI / OWI


In Wisconsin, refusing a breathalyzer test after being arrested for suspected drunk driving can result in the suspension of your driver’s license. However, what many people do not know is that a roadside blood alcohol content (BAC) test is voluntary. Due to the danger of license suspension, many people submit to a breathalyzer test and live with the results that come from it. However, breathalyzer tests are not always 100 percent accurate, and there are ways to challenge the results in Wisconsin courts.

Tests Used By Police to Determine BAC

A breathalyzer test is a way to measure the amount of alcohol in someone’s body by taking a breath sample. In Wisconsin, a person can be convicted of drunk driving if it is determined that his or her blood alcohol content is .08 or higher. While the courts generally consider breathalyzer tests to be reliable, blood tests are widely regarded as the most reliable means to test BAC. Urine tests have also been used to measure BAC; however, those tests are often less reliable than breathalyzer or blood tests.

Common Challenges to Breathalyzer Tests

One of the most common ways to challenge the results of a breathalyzer test is to show that the device was not in proper working order. These devices need to be calibrated regularly, and they must receive maintenance on a schedule. Logs for the breathalyzer machine you gave a sample to can be requested and scrutinized. In addition, the officer administering the test must have undergone training and must have given the test in accordance with that training.

Another way to challenge breathalyzer test results is to show that alcohol-containing substances in the mouth gave off an incorrectly elevated reading. This occurs because the substance in the mouth is closer to the breathalyzer that the air coming from the lungs. Common culprits are toothache treatments, mouthwash, and burping or vomiting.

It should be noted that even if the breathalyzer results are successfully thrown out, prosecutors may still attempt to prove that you were drunk by other means, such as an officer’s observations of certain behavior like slurring of words or inability to walk in a straight line. By working with a skilled attorney, you can determine the best defense against these claims as you seek to avoid an OWI conviction.

Call a Milwaukee OWI Defense Lawyer

If you were charged with an OWI, and you believe that your breathalyzer test was inaccurate, you should speak to the lawyers at Gimbel, Reilly, Guerin & Brown LLP. Our experienced Milwaukee, WI OWI attorneys will review your case and determine the best strategy to take to minimize the consequences you may face. Call our offices today at 414-271-1440.



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