Wis. Stat. § 344.21

Neither the report required following an accident, the action taken by the department pursuant to this chapter, the findings, if any, upon which such action is based nor the security filed as provided in this chapter shall be referred to in any way or be any evidence of the negligence or due care of either party at the trial of any action at law to recover damages, but this shall not be construed to exclude a notice of insurance filed pursuant to s. 344.14 or 344.15 (4), or both, from being admissible in evidence where it would otherwise be material and admissible under the rules of evidence.