(1) The state and local governments are not liable for any injury received by a third-party occupant of a vehicle that is owned, leased, or rented by the state or local government if, at the time the injuries were inflicted, the third-party occupant was:
(a) Riding in or on the vehicle with a state or local government employee who had explicitly acknowledged in writing the employer's policy on use of vehicles owned, leased, or rented by the state or local government; and
(b) Not specifically and expressly authorized by the state or local government to be an occupant of the vehicle.
(2) For purposes of this section, "third-party occupant" means a person who occupies a vehicle owned, leased, or rented by the state or local government and who is not an officer, employee, or agent of the state or local government. "Local government" includes any city, county, or other subdivision of the state and any municipal corporation, quasi-municipal corporation, or special district within the state.