The State Highway Commission is hereby authorized to promulgate regulations governing the issuance of permits for the erection and maintenance of outdoor advertising coming within the exceptions contained in subsections (a), (d) and (e) of Section 49-23-5, 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 Section 49-23-1, and consistent with the national standards promulgated by the secretary of commerce pursuant to Title 23, United States Code, provided that such regulations shall not contain any definition more restrictive than those set forth in Section 49-23-3; nor shall they be more restrictive than the provisions set forth in Section 49-23-9.