226.510.  Definitions. — As used in sections 226.500 to 226.600, the following words or phrases mean:

  (1)  "Freeway primary highway", that part of a federal-aid primary highway system, as of June 1, 1991, which has been constructed as divided, dual lane fully controlled access facilities with no access to the throughways except the established interchanges.  When existing two-lane highways are being upgraded to four-lane limited access, the regulations for freeway primary highways shall apply as of the date the state highways and transportation commission acquires all access rights on the adjoining right-of-way;

  (2)  "Interstate system", that portion of the national system of interstate highways located within the boundaries of Missouri, as officially designated or may be hereafter designated by the state highways and transportation commission with the approval of the Secretary of Transportation, pursuant to Title 23, United States Code, as amended;

  (3)  "Outdoor advertising", an outdoor sign, display, device, figure, painting, drawing, message, plaque, poster, billboard, or other thing designed, intended or used to advertise or inform, any part of the advertising or information contents of which is visible from any point of the traveled ways of the interstate or primary systems;

  (4)  "Primary system", the federal-aid primary highways as of June 1, 1991, and all highways designated as part of the National Highway System by the National Highway System Designation Act of 1995 and those highways subsequently designated as part of the National Highway System;

  (5)  "Rest area", an area or site established and maintained within or adjacent to the highway right-of-way under public supervision or control, for the convenience of the traveling public, except that the term shall not include automotive service stations, hotels, motels, restaurants or other commerce facilities of like nature;

  (6)  "Urban area", an urban place as designated by the Bureau of the Census, having a population of five thousand or more within boundaries to be fixed by the state highways and transportation commission and local officials in cooperation with each other and approved by the Secretary of Transportation, or an urbanized area as designated by the Bureau of the Census within boundaries to be fixed by the state highways and transportation commission and local officials and approved by the Secretary of Transportation.  The boundary of the urban area shall, as a minimum, encompass the entire urban place as designated by the Bureau of the Census.