Ohio Rev. Code § 4511.0912: Speeding tickets.

A local authority shall not issue a ticket for a violation of section 4511.21 or 4511.211 of the Revised Code or a substantially equivalent municipal ordinance due to failure to observe the applicable speed limit based upon evidence recorded by a traffic law photo-monitoring device unless one of the following applies:

(A) For a system location that is located within a school zone or within the boundaries of a state or local park or recreation area, the vehicle involved in the violation is traveling at a speed that exceeds the posted speed limit by not less than six miles per hour.

(B) For a system location that is located at any other location, the vehicle involved in the violation is traveling at a speed that exceeds the posted speed limit by not less than ten miles per hour.