Prior to trial, Laumann had provided the State with exhibits he intended to introduce at trial. The State moved to exclude one of the exhibits, a document which indicated that the intoxilyzer 5000 which had been used to test Laumann's breath had malfunctioned 153 times. The trial court granted the motion, ruling that the document was irrelevant and would be confusing without any expert witness to explain it. The jury convicted Laumann. He now appeals.
Admissibility of evidence is a discretionary determination for the trial court.
This court will not reverse a discretionary ruling unless the trial court erroneously exercised its discretion. After reviewing the record and briefs, this court concludes that the trial court's decision to exclude the document proffered by Laumann constituted an erroneous exercise of discretion. Wisconsin courts have specifically held that the issue of whether a breath test is reliable is a defense to a drunk driving charge. The document proffered by Laumann attempted to provide an argument for such a defense. One way to prove whether a breath test is reliable is to challenge the reliability of the intoxylizer.