Challenging Breath Test Results

If you are pulled over on suspicion of DUI, you may be forced to take a breathalyzer test. Many police officers rely on these DUI tests in determining whether there is probable cause to arrest you. Once in custody, the police will ask you to submit to another breath test, the result of which will be used as evidence against you by the prosecution in your DUI case. Thus, if you want to avoid the harsh consequences of a DUI, your Chicago criminal defense lawyer may need to focus on challenging breath test results.

Blood tests are the most accurate when determining your blood alcohol content (BAC). However, blood tests are invasive and inconvenient. They cannot be done on the side of the road like a breath test. Many factors can affect the results of breathalyzers. In some cases, the reading may register twice as much as the actual BAC.

If you are facing DUI charges, call Chicago DUI lawyer Michael O’Meara today at 312-909-0706 to see whether you can get your breath test results excluded from your case.

How Do Breath Tests Work?

Breathalyzer tests all work the same way. You blow into a mouthpiece while the device registers a reading of your BAC. Professional grade breath tests use fuel cell technology and are the most accurate. You can also purchase personal ones that rely on semiconductor technology. Even professional grade tests are prone to error.

Challenging a Breath Test

A breathalyzer test can be challenged in many ways. Your lawyer can challenge the results of the roadside breath test that supposedly gave the police probable cause to arrest you for drunk driving. If your lawyer successfully argues that the police lacked probable cause to arrest you, your charges may get dismissed.

Your lawyer can also challenge the results of the breath test you took at the police station, in which case the judge may remove the test results from the prosecutor’s case. This will vastly enhance your chances of avoiding a conviction.

Here are some common tactics in challenging the use of breath tests:

  • The breathalyzer was unreliable. If you blow into a breathalyzer several different times and get dramatically different readings each time, it’s likely that the device is not reliable. In fact, some judges have claimed that certain brands are not accurate.
  • Only one test was performed. A police officer must perform multiple breath tests to ensure the device is working properly. Otherwise, the results cannot be used in court.
  • The results were out of range. Breath tests must be performed until two consecutive results are within 0.020 percent of each other. If the range is more than that, then a court may consider the test results to be inconclusive.
  • Foreign substances were present. You may have ingested a product that contained alcohol, which skewed the breath test results. For example, breath fresheners, mouthwash, and certain medications contain alcohol. Your lawyer can argue that this is why your test result exceeded the legal limit.
  • The machine malfunctioned or was not calibrated properly. Breathalyzers must undergo routine maintenance. They must be calibrated at regular intervals in order to be considered accurate. In addition, all records must be kept on file. If the prosecutor fails to prove in court that the device was calibrated properly and maintained, the results of the test may be excluded from the case.
  • The breathalyzer operator did not have adequate training. The police officer administering the test must have had proper training that involves the specific kind of breathalyzer being operated. Your lawyer can point to the officer’s lack of training as a reason for excluding your breath test results from the case.
  • The breath test was administered incorrectly. Breath tests require some attention to detail, which means user error is common. If there is evidence that the officer did not correctly administer the test, you can use this as a defense.
  • The breathalyzer was used illegally. A breath test cannot be used on just any driver on the road. The police officer must have reasonable suspicion that you were under the influence of alcohol or drugs to give you a roadside breath test. To give you a breath test at the station, the police must have probable cause to arrest you on suspicion of DUI. If your Chicago DUI lawyer can show that the police lacked either reasonable suspicion or probable cause, the breath test results may be suppressed from the prosecutor’s case.
  • Other chemicals interfered with the test. Nasal sprays, paint fumes, adhesives, and plastics present in the area where the breath test occurs can create false positives. It may be necessary to move to a different environment to get an accurate result. If the police failed to do so, the test result may be inadmissible as evidence.
  • The breath sample was too long. For best results, you should breathe into the device for no more than 10 seconds. A longer breath could cause your BAC to rise to an inaccurate level. If there is evidence that the officer made you breathe into the test machine for too long, the judge may exclude the result from your case.

Get Legal Help to Challenge Your Breath Test Results

Breathalyzer tests are not always accurate. At O’Meara Law, we will carefully review all of the records pertaining to the administration of your breath test to determine whether the results may be challenged. This is one of the most effective methods of defeating DUI charges.

Many of the defenses listed above may be used in your situation. To find out which ones, call attorney Michael O’Meara today at 312-909-0706 for a free and confidential case assessment