A breath test measures your blood alcohol concentration, and it’s useful for police officers because the law sets the legal limit at 0.08%. If someone is over this legal limit while operating their vehicle, the officer can presume that they are impaired and make an arrest.
Those who are facing arrest may assume that the breath test guarantees that they will be convicted. They see it as indisputable evidence, which is much different than an officer’s personal account of how they were driving or how they did on field sobriety tests. A breath test feels much more scientific. But the reality is that it could be wrong.
Was the officer trained?
First and foremost, the officer needs to be trained in order to use the breath test correctly. If they lacked training or made mistakes, there’s no way to know if the results they got are accurate.
Was the test calibrated?
Similarly, the test itself needs to be calibrated at certain times, and there may be tasks that are necessary for maintenance and upkeep. If police officers have not carried out these calibrations, do they really know that you were over the legal limit? Perhaps the test just gave an inaccurate result.
Did anything else influence the results?
Finally, there are some outside factors that could cause you to have a high reading. For instance, maybe you burped during the test, putting more alcohol content into your breath. Or, perhaps you recently used mouthwash, so you tested positive for alcohol even though you hadn’t been drinking.
As you can see, a breath test is no guarantee of a conviction. Just make sure you know what legal defense options you have.