Iowa Code § 321P.3: Use limited.

1. A local authority shall not use an automated or remote system for traffic law enforcement to issue a citation for a traffic violation unless the violation is for exceeding the speed limit by more than ten miles per hour.

2. A local authority with a population of twenty thousand or less based on the most recent federal decennial census shall not use a mobile system to issue a citation for a traffic violation. The department shall adopt rules pursuant to chapter 17A otherwise authorizing and regulating the operation of mobile systems, taking into consideration a mobile system’s mobility, flexible usage, and the needs of a local authority to control traffic speed to address critical traffic safety issues at a location. However, the rules shall not authorize the use of a mobile system other than in neighborhoods, construction zones, school zones, including collegiate zones, and locations where traffic enforcement is difficult or dangerous to enforce by alternative methods.

3. A local authority, regardless of its population, may issue a warning memorandum to the owner of a vehicle that was operated in violation of a traffic law if the violation was detected by an automated or remote system for traffic law enforcement, including a mobile system.