S.C. Code Ann. § 56-11-20: Enforcement of motor carrier road tax provisions; International Fuel Tax Agreement (IFTA).

The Department of Motor Vehicles and the Department of Public Safety each shall enforce this chapter with respect to the possession of correct registration and display of the proper identification marker. Notwithstanding other provisions of this chapter, the department may enter into an agreement with other states in a registration and identification marker reciprocal agreement known as the International Fuel Tax Agreement (IFTA). Qualified vehicles operating in accordance with this agreement are not required to purchase other fuel markers in member states.