(a) After survey to determine existing outdoor advertising structures in this state and after public hearing, the State Highway Commission shall determine customary use in the display of outdoor advertising in this state with regard to size, lighting, and spacing in areas zoned commercial or industrial and in unzoned areas used for commercial or industrial purposes.

(b) The definition of an unzoned commercial or industrial area shall be determined by agreement between the commission and the United States Secretary of Transportation but shall be no more restrictive than that required by Title 23 of the United States Code. The commission shall then adopt and promulgate regulations governing the issuance of permits for the erection and maintenance of outdoor advertising coming within the purview of this chapter, consistent with the safety and welfare of the traveling public, and as may be necessary to carry out the policy of the state declared in this chapter consistent with customary usage, the purposes of this chapter, and in agreement with the United States Secretary of Transportation.

(c) In the event that federal statutes, rules, or regulations conflict with the provisions of §§ 27-74-210 -- 27-74-212 or regulations promulgated thereunder, the commission is authorized to promulgate rules and regulations necessary to comply with federal law after first obtaining the advice of the Legislative Council thereon while pursuing, insofar as possible, the legitimate objectives of those sections.