All state-owned motor vehicles shall bear on the rear license plates issued by the Division of Motor Vehicles the notation “STATE OWNED.” All state-owned boats shall bear prominent identification on the rear thereof identifying such boats as state-owned. The automobile used by the Governor, and law-enforcement vehicles and vessels of State agency law-enforcement personnel covered under the provisions of the Delaware Council on Police Training, are exempted from the requirements of this section. Other exemptions from this section must be approved by the Director of the Office of Management and Budget.