As used in this chapter:

(1)  “Information center” means an area or site established and maintained as safety rest areas for the purpose of informing the public of places of interest within the state and providing such other information as the director of transportation may consider desirable.

(2)  “Interstate system” means that portion of the national system of interstate and defense highways located within this state, as officially designated, or as may hereafter be so designated, by the director of transportation, and approved pursuant to the provisions of title 23, United States Code, Highways.

(3)(i)  “Maintenance” means the normal repair of outdoor advertising due to wear and tear. Maintenance shall not include the relocation nor the increase of advertisement size nor height. Maintenance shall not permit any alterations such as the addition of face lighting nor lit panels, moving parts, sparkling surfaces, cutouts nor temporary extensions of advertising space.

(ii)  Maintenance shall permit the change in the advertisement copy by means of trivision technology or other equivalent technology approved by the department of transportation and, if necessary, the federal highway administration; provided, however, for each sign using such technology two (2) valid permits for signs of equivalent size shall be required. Provided, further, however, that in the event that a person, firm or corporation does not hold more than one permit, only one permit for signs of equivalent size shall be required.

(4)  “Outdoor advertising” means an outdoor sign, display, light, device, figure, painting, drawing, message, plaque, poster, billboard, structure, 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-traveled way of the interstate, primary, or secondary systems.

(5)  “Primary systems” means that portion of connected main highways, as officially designated, or as may hereafter be so designated, by the director of transportation, pursuant to the provisions of title 23, United States Code, Highways.

(6)  “Safety rest area” means 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.

(7)  “Secondary systems” means that portion of state maintained roads that are neither interstate nor primary roads.