(a) 23 U.S.C. 131(d) provide that signs “may be erected and maintained within 660 feet of the nearest edge of the right-of-way within areas . . . which are zoned industrial or commercial under authority of State law.” Section 131(d) further provides, “The States shall have full authority under their own zoning laws to zone areas for commercial or industrial purposes, and the actions of the States in this regard will be accepted for the purposes of this Act.”

(b) State and local zoning actions must be taken pursuant to the State's zoning enabling statute or constitutional authority and in accordance therewith. Action which is not a part of comprehensive zoning and is created primarily to permit outdoor advertising structures, is not recognized as zoning for outdoor advertising control purposes.

(c) Where a unit of government has not zoned in accordance with statutory authority or is not authorized to zone, the definition of an unzoned commercial or industrial area in the State-Federal agreement will apply within that political subdivision or area.

(d) A zone in which limited commercial or industrial activities are permitted as an incident to other primary land uses is not considered to be a commercial or industrial zone for outdoor advertising control purposes.