The police will often assume that a breath test is correct. If you take a test and your blood alcohol concentration (BAC) is at 0.09%, for example, they are likely to charge you with impaired driving.
But that does not necessarily mean the test is accurate. Do not assume that a conviction is guaranteed. You still have plenty of defense options, and there are many reasons why a breath test could be inaccurate.
Radio frequency interference
One potential issue is if there is radio or electrical interference from other devices in the area. This could affect the reading that the device outputs, possibly inflating it artificially. If this casts doubt on the results, the test may be inadmissible in court. This is most common with older breath test devices.
Officer mistakes
The police officer administering the test may also have made a mistake. Maybe they did not follow the proper steps, or they misunderstood the testing protocol. In some cases, the officer may not have received the necessary training to perform the test correctly, leaving the results in question.
Calibration issues
Finally, the breath test device itself could simply be inaccurate. When was the last time it was calibrated and maintained? If the police department does not have recent calibration records, that could call the test’s reliability into doubt. A neglected device may still be used—but it may produce inaccurate results even when used properly.
When facing impaired driving charges, it is important to understand all of the potential defense strategies available and the steps you need to take moving forward.