If you are facing DUI charges in Wisconsin, it is highly likely that the police have breathalyzer test results stating that you were drunk while driving. It is also likely that this is a major part of their case against you. The good news is that it is possible to challenge breathalyzer readings in some cases, the same way you can challenge the readings of a radar gun in a speeding ticket case.
There are two main ways to challenge breathalyzer test results. The first is to challenge the functionality of the machine itself, and the section is to challenge the authority of the officer that gave you a breathalyzer test.
How do I challenge the machine?
Since breathalyzers are machines, there is always the possibility that the machine itself is faulty. For example, a court case in Iowa had a man blowing into a breathalyzer machine in the courtroom. The machine recorded him as drunk, even though he was completely sober and in court.
Even if the machine itself is not faulty, if the police did not calibrate the machine prior to its use the readings may be incorrect. Usually the police will give testimony saying that an officer calibrated the machine at the time of its use. However, if they cannot give this testimony the court may throw out the results.
How do I challenge the police officer?
As with radar guns, police officers must have had training on breathalyzers before using them. Again, usually the police will give testimony to this point. But if the police cannot give this testimony, again, the courts may throw out the results.