Mich. Comp. Laws § 257.1807

Sec. 7. (1) "School bus" means a motor vehicle with a manufacturer's rated seating capacity of 11 or more passengers, including the driver, used for the transportation of preprimary, primary, or secondary school pupils to or from school or school-related events or a multifunction school activity bus manufactured after September 2, 2003 as defined in 49 CFR 571.3, 49 CFR 571.108, and 49 CFR 571.131. School bus does not include a vehicle operated by a public transit agency or authority. A vehicle that is not a school bus is not subject to this act. For the purposes of this act, a parent, or legal guardian transporting his or her child or another child with written permission of the other child's parent or legal guardian on a school-related event is not subject to this act. (2) "Type I school bus" means a school bus with a gross vehicle weight rating of more than 10,000 pounds. (3) "Type II school bus" means a school bus with a gross vehicle rating of 10,000 pounds or less.