Iowa Code § 321I.11: Accident reports.

If an all-terrain vehicle is involved in an accident resulting in injury or death to anyone or property damage amounting to one thousand five hundred dollars or more, either the operator or someone acting for the operator shall immediately notify the county sheriff or another law enforcement agency in the state. If the accident occurred on public land, public ice, or a designated riding trail under the jurisdiction of the commission, the operator shall file with the commission a report of the accident, within seventy-two hours, containing information as the commission may require. All other accidents shall be reported as required under section 321.266.