S.C. Code § 56-3-663
The Department of Motor Vehicles is authorized to enter into reciprocal agreements with the regulatory agencies of other states having jurisdiction and authority over motor carriers to provide for base state agreements in which the registration of interstate carriers operating in participating states may be accomplished by registration in one base state. Carriers registering in this State under these agreements are subject to the jurisdiction and authority of the Department of Public Safety and the Department of Motor Vehicles for enforcement purposes. When the carrier's base state is South Carolina, the Department of Motor Vehicles may require further filings of certificates of insurance, surety bonds, and other documents to show the carrier's qualifications to operate. Participating carriers shall register their authority directly with the Department of Motor Vehicles and not with other state or local agencies.
S.C. Code § 56-3-663