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Are breathalyzers always accurate?

On behalf of Dolan + Zimmerman LLP May 1, 2019

It’s a rather common scenario: You’re driving home from a night out with friends and suddenly you see flashing lights behind you. You don’t think you’re speeding or doing anything wrong, so you quickly start to pull over – assuming the officer is on his way to an important call. It’s shocking when the patrol car pulls over right behind you and you see the officer making their way to your driver’s side window.

Have you been drinking?

After asking for your driver’s license and insurance, asking if you have been drinking is a common question. If you are honest and say that yes, you have had one beer, the officer may suspect that you have actually had more than one, especially if he or she can smell alcohol on your breath or for some other reason suspects that you are driving while you are impaired or intoxicated.

If the officer believes that they have probable cause to believe that you are impaired or intoxicated, they may as you to participate in field sobriety tests, and may ask you to submit to a portable breath test.

And while you could be thinking up until this point that you have nothing to worry about since you are clearly sober, portable breath tests are not always accurate and you could wind up getting arrested, even if you really drank very little.

Challenging the validity of a breath test

A blood or breath test is the most accurate when it comes to figuring out someone’s blood alcohol level, but a police officer is not going to be drawing your blood or administering a breath test on the side of the road. Rather, an officer will typically ask you to breath into a portable breath testing device, typically referred to as a PBT. This small handheld device gives an estimate of a driver’s blood alcohol content. The results of PBTs are not admissible in court, but can inform officers’ decisions regarding arrest.

Even blood tests and non-roadside breath tests can yield inaccurate results if the officer using the breath test is not properly trained or is not following their training, if the blood test is not administered properly, or if the testing equipment is not properly calibrated. Questions regarding equipment certification and officer training are common reasons for a criminal defense attorney to challenge the results of a breath test.

A successful challenge of the breath test results could result in test results being admissible in court, or in test results being deemed unreliable in driver’s license proceedings at the Department of Revenue. This means the prosecutor may be forced to attempt to use other evidence – the officer’s testimony to your driving behavior or the way you visually looked or the smell of alcohol on your breath, for example — to prove that you were impaired or intoxicated. This can significantly weaken the case against you.

In order to determine whether or not it is possible to challenge the results of a blood or breath test, and in order to successfully pursue such a challenged, you will need to work with an experienced attorney who has experience handling DUI cases and challenging the results of breath tests.