"School bus" means every bus designed for carrying more than nine passengers that is owned by a public, private or governmental agency or institution of learning and operated for the transportation of children to or from a school session or a school function, or owned by a private person and operated for compensation for the transportation of children to or from a school session or a school function. However, "school bus" does not include a bus operated by a municipally owned transportation system, a mass transit company operating exclusively within the territorial limits of the Municipality, or within such limits and the territorial limits of municipal corporations immediately contiguous to the Municipality, nor a common passenger carrier certified by the Public Utilities Commission unless such bus is devoted exclusively to the transportation of children to and from a school session or a school function, and "school bus" does not include a van or bus used by a licensed child day-care center or Type A family day-care home to transport children from the child day-care center or Type A family day-care home to a school if the van or bus does not have more than fifteen children in the van or bus at any time.
(ORC 4511.01(F))