Ok, so here is the Cedar Rapids ordinances:
https://www.municode.com/library/ia/cedar_rapids/codes/code_of_ordinances
Traffic cameras are under Chapter 61. (e)(2) is the provision moving this from administrative to judicial. At that point you could conceivable challenge the certification and whatnot of the device.
Vehicle Owner's Civil Liability for Certain Traffic Offenses.
1. The Vehicle Owner shall be liable for a fine as imposed below if such a vehicle crosses a marked stop line or the intersection plane at a system location when the traffic signal for that vehicle's direction is emitting a steady red light or arrow.
2. The Vehicle Owner shall be liable for a fine as imposed below if such vehicle travels at a speed above the posted limit.
3. The violation may be exempted from liability as outlined below in subsection (f.) of this section, and other defenses may be considered in connection with the appeal process.
4. In no event will an Automated Traffic Citation be sent or reported to the Iowa Department of Transportation or similar department of any other state for the purpose of being added to the Vehicle Owner's driving record.
(e) Contesting an Automated Traffic Citation. A Vehicle Owner who has been issued an Automated Traffic Citation may contest the citation as follows:
1. By submitting in a form specified by the City a request for an administrative hearing to be held at the Cedar Rapids Police Department before an administrative appeals board (the "Board") consisting of one or more impartial fact finders. Such a request must be filed within 30 days from the date on which Notice of the violation is sent to the Vehicle Owner. After a hearing, the Board may either uphold or dismiss the Automated Traffic Citation, and shall mail its written decision within 10 days after the hearing, to the address provided on the request for hearing. If the citation is upheld, then the Board shall include in its written decision a date by which the fine must be paid, and on or before that date, the Vehicle Owner shall either pay the fine or submit a request pursuant to the next paragraph, (e.)(2.).
2. By submitting in a form specified by the City a request that in lieu of the Automated Traffic Citation, a municipal infraction citation be issued and filed with the Small Claims Division of the Iowa District Court in Linn County. Such a request must be filed within 30 days from the date on which Notice of the violation is sent to the Vehicle Owner. Such a request will result in a court order requiring the Vehicle Owner to file an answer and appearance with the Clerk of Court, as well as setting the matter for trial before a judge or magistrate. If the Court finds the Vehicle Owner guilty of the municipal infraction, state mandated court costs will be added to the amount of the fine imposed by this section.
(f) Exceptions to Owner Liability. There shall be no liability pursuant to this section if:
1. The operator of the vehicle in question was issued a uniform traffic citation for the violation in question pursuant to Cedar Rapids Code Chapter 61 or Iowa Code Chapter 321 (2008); or
2. The violation occurred at any time after the vehicle in question or its state registration plates were reported to a law enforcement agency as having been stolen, provided, however, the vehicle or its plates had not been recovered by the Vehicle Owner at the time of the alleged violation; or
3. The vehicle in question was an authorized emergency vehicle; or
4. The officer inspecting the recorded image determines that the vehicle in question was lawfully participating in a funeral procession; or
5. The officer inspecting the recorded image determines that the vehicle in question entered the intersection in order to yield the right-of-way to an emergency vehicle.
(g) Failure to Timely Pay or Appeal. If the recipient of an Automated Traffic Citation does not either pay the fine by the due date stated in the citation or appeal the citation as provided herein, a municipal infraction citation may be filed by the Cedar Rapids Police Department and a fine may be sought in accordance with Cedar Rapids Code
section 1.12 rather than subsection (d.) above. If the Court finds the Vehicle Owner guilty of the municipal infraction, state mandated court costs will be added to the amount of the fine imposed by this section.