Mass. Gen. Laws ch. 93D § 1
In this chapter unless the context otherwise requires, the following words shall have the following meanings:
"Interstate system", that portion of the national system of interstate and defense highways located within this commonwealth, as officially designated, or as may be hereafter so designated, by the department of public works of the commonwealth, and approved by the United States Secretary of Transportation, pursuant to the provisions of Title 23, United States Code, "Highways".
"Primary systems", that portion of connected main highways, as officially designated, or as may hereafter be so designated, by the department of public works of the commonwealth, and approved by the United States Secretary of Transportation, pursuant to the provisions of Title 23, United States Code, "Highways".
"Outdoor advertising", any outdoor sign, display, light, device, figure, painting, drawing, message, plaque, poster, billboard, or other thing which is designed, intended or used to advertise or inform, any part of the advertising or information contents of which is visible from any place on the main travelled way of the interstate or primary systems.
"Safety rest area", an area or site established and maintained within or adjacent to the right of way by or under public supervision or control, for the convenience of the traveling public.
"Secretary", the United States Secretary of Transportation.
"Urban area", urban area as defined in subsection (a) of section 101 of Title 23 of the United States Code.
"Board", outdoor advertising board.
"Information center", an area or site established and maintained at safety rest areas for the purpose of informing the public of places of interest within the state and providing such other information as the department of highways may consider desirable.
"Department", the department of highways of the commonwealth.
Mass. Gen. Laws ch. 93D, § 1