If the police are charging you with drunk driving, it is likely that a key piece of evidence is a breathalyzer reading. In fact, in some cases, the entire DUI case hinges on a breathalyzer reading.
Breathalyzer results are very similar to radar gun results. It is entirely possible to contest breathalyzer results in certain situations. According to FindLaw, the two most common ways to challenge breathalyzer results are to challenge the reliability of the machine itself or the officer who gave the breathalyzer test.
How can I challenge the machine?
It is possible that the breathalyzer machine itself is not reliable. In a case in Iowa, the accused blew into a breathalyzer machine during the trial itself when he was totally sober. The breathalyzer machine produced a ‘HI’ reading regardless. Clearly, the machine was faulty.
The other way is to challenge the calibration of the breathalyzer machine. In order for a breathalyzer to give accurate results, the officer using it must calibrate it properly. Usually, the police will provide testimony to the fact that the officer calibrated the machine. If the police cannot provide this testimony, the court may throw out the results.
How can I challenge the officer?
Any officer who uses a breathalyzer machine must have training. Again, normally the police will provide testimony proving that the officer had been properly trained on the machine.
Breathalyzer tests must also be legal. In order for a breathalyzer test to be legal, the police officer must have reasonable suspicion to pull you over in the first place: this means providing testimony regarding erratic driving on your part.