Notwithstanding any other provision of law, the State of North Carolina hereby finds and declares that the removal of certain directional signs, displays, and devices, lawfully erected under State law in force at the time of their erection, which do not conform to the requirements of subsection (C) of 23 U.S.C. § 131, which provide directional information about goods and services in the interest of the traveling public, and which were in existence on May 6, 1976, may work a substantial economic hardship in certain defined areas, and shall be exempt according to Section 131 United States Code and the rules and regulations promulgated pursuant thereto. (1977, c. 639.)