Criminal Defense Lawyer Serving Ann Arbor

When was that breath test last calibrated?

The police pull you over one rainy night on the way home, the red and blue lights smeared across your rear window, and they ask you to take a breath test. The officer gets the Breathalyzer out, has you blow into it and then nods knowingly. She tells you to get out and get in the back of the squad car: You're over the .08 limit, and you're going to jail.

A lot of people just accept it; that's what the test said, after all. It's not like the officer made a judgment call - she has solid test results to back up the arrest. Even if you think you're sober - you feel fine, and all you did was have one drink with dinner - you may just assume that you were unknowingly over the limit and can't beat the charges.

Neglected tests

You don't have to accept the results of a test without question. Breath tests can be wrong, and they must be properly maintained and calibrated to give accurate results. If they are neglected or carried around in squad cars without ever being examined properly, who knows what the results really mean? A person who is sober could register over the legal limit, while someone far over the limit could blow into it and be found sober.

Calibration guidelines

Generally speaking, the police must follow these guidelines when they use breath tests:

  • The breath tester has to be on a list of approved devices.
  • Police officers have to be trained and certified to use that specific test.
  • The test must be done without outside factors that could influence it. For instance, if the person eats or burps, it could throw off the test.
  • The officer has to follow the training exactly when having the person use the device.
  • The Breathalyzer has to get two different results, and the readings need to be close - usually within .02. If they are not, this could indicate that the test is faulty, hasn't been calibrated recently enough and hasn't been maintained properly.

While these rules are more general, it's important to note that specific rules vary from state to state. In Michigan, each test has to be checked and calibrated roughly once a week. The two calibrations can't have more than 14 days in between, though they don't have to be carried out exactly every seven days.

False readings

Were you arrested after being given a breath test with results that surprised you? If so, it's possible that the test was faulty, neglected and unreliable. It's also possible that the test had not been calibrated in more than the 14-day maximum. When this happens, you have to know all of the defense options that you have as you face your OWI charges.