No outdoor advertising shall be erected in this state except the following:

(1)  Directional and other official signs and notices erected, maintained, or authorized by a public agency or body, which signs and notices shall include, but not be limited to, signs and notices pertaining to natural wonders and scenic and historic attractions, as authorized or required by law.

(2)  Signs, displays, and devices advertising the sale or lease of property upon which they are located, subject, however, to the national standards as promulgated pursuant to the federal Highway Beautification Act of 1965.

(3)  Signs, displays, and devices advertising activities conducted on the property upon which they are located, subject, however, to the national standards as promulgated pursuant to the federal Highway Beautification Act of 1965 including spacing requirements of the Rhode Island department of transportation rules and regulations governing outdoor advertising, except for signs that are allowed to be relocated as permitted in subsection (5).

(4)  Bus shelters erected under the authority of the state department of transportation or Rhode Island public transit authority which shall be permitted no more than one two (2) sided sign. Each sign face shall be no more than twenty-four (24) square feet in size.

(5)  Lawfully permitted signs, displays, and devices already in existence may be relocated to other permitted locations with the approval of the appropriate governmental agency(s), provided that the relocated outdoor advertising remains the same or smaller in size, and that such outdoor advertising conforms and is consistent with the municipal comprehensive plan and related zoning requirements.

(6)  This chapter shall not preclude the maintenance of existing outdoor advertising.