The Department of Transportation is hereby authorized and empowered to fix higher weight limitations at reduced speeds for vehicles used in transporting property when the point of origin or destination of the motor vehicles is located upon any light traffic highway, county road, farm-to-market road, or any other roads of the secondary system only and/or to the extent only that the motor vehicle is necessarily using said highway in transporting the property from the bona fide point of origin of the property being transported or to the bona fide point of destination of said property and such weights may be different from the weight of those vehicles otherwise using such roads.
N.C. Gen. Stat. § 20-118.2