N.C. Gen. Stat. § 20-121

The Department of Transportation or local authorities may prohibit the operation of vehicles upon or impose restrictions as to the weight thereof, for a total period not to exceed 90 days in any one calendar year, when operated upon any highway under the jurisdiction of and for the maintenance of which the body adopting the ordinance is responsible, whenever any said highway by reason of deterioration, rain, snow or other climatic conditions will be damaged unless the use of vehicles thereon is prohibited or the permissible weights thereof reduced. The local authority enacting any such ordinance shall erect, or cause to be erected and maintained, signs designating the provisions of the ordinance at each end of that portion of any highway to which the ordinance is applicable, and the ordinance shall not be effective until or unless such signs are erected and maintained.