Iowa Code § 805.13: Venue.

1. Traffic violations, whether or not scheduled, and all other scheduled violations may be tried before the nearest magistrate in the judicial district in which the offense is committed, or if the offense occurred in a city which is located in two counties, the violation shall be tried as provided in section 803.3, subsection 5.

2. Upon written consent of the defendant and the officer issuing the citation, traffic violations, whether or not scheduled, and any other scheduled violations, other than those for which a court appearance is required under section 805.10 may be prosecuted in any county in the state irrespective of where committed, and in such event the documents in the case shall be sent to the court or traffic and scheduled violations office designated by the defendant and the officer.