Wisconsin Statutes Motor Vehicles (Ch. 110) § 110.064. Motor buses used for pupil transportation

(1)(a) Notwithstanding s. 340.01(56)(b)4., no motor bus operated under contract as provided in s. 121.55(1)(a) or (d) may be used for the purpose of transporting pupils to or from a public or private school as provided in s. 340.01(56)(a)1. and no motor bus otherwise operated on a special route for the purpose of transporting pupils to or from a public or private school as provided in s. 340.01(56)(a)1. may be used for that purpose unless the motor bus satisfies safety and operation standards specified by the department under par. (b).

(b) The department shall promulgate and enforce a rule requiring that a motor bus under par. (a) satisfy safety standards providing an equivalent level of safety as the safety standards specified by the department for a school bus having the same gross vehicle weight rating and operation standards specifying that the rear door of a motor bus under par. (a) may not be used for the entry or exit of pupils, except in an emergency, except that the department may not promulgate a rule which is in conflict with federal law, which requires the motor bus to be painted in accordance with s. 347.44(1), or which requires the motor bus to be equipped with flashing red or flashing red and amber warning lights as specified in s. 347.25(2).