In a specified simple misdemeanor other than one charged upon a uniform citation and complaint a court may accept a forfeiture of collateral security in lieu of appearance, as a proper disposition of a case. Each judicial district, by action of a majority of the district judges, may determine the misdemeanors subject to such disposition and promulgate by rule a list of same and disseminate to all magistrates in the district. A copy of such rule shall be transmitted to the clerk of the supreme court. Prior to termination of the case by forfeiture under this rule, the defendant must execute a written request for same. Unless vacated upon application within 30 days of the forfeiture, such forfeiture shall constitute a conviction in satisfaction. In the event a simple misdemeanor is charged upon the uniform citation and complaint defined in Iowa Code section 805.6, and the defendant either has submitted unsecured appearance bond as provided in that section or has submitted bail as provided in Iowa Code section 805.9, subsection 3, the court or the clerk of the district court may enter a conviction pursuant to the defendant’s written appearance and may enter a judgment of forfeiture of the collateral in satisfaction of the judgment and sentence; provided that if the defendant submitted unsecured appearance bond or if bail remains uncollected, execution may issue upon the judgment of the court at any time after entry of the judgment.