S.C. Code Ann. § 57-5-160

The Department of Transportation is authorized to enter into agreement with the United States Atomic Energy Commission and such other parties as may be necessary to accept and place into the state highway system portions of the highways formerly designated as Nos. 28 and 125 lying within the boundaries of the Savannah River Project. The department, after consultation with the Atomic Energy Commission, shall promulgate rules and regulations governing the manner in which the highway within the Savannah River Project may be utilized by the traveling public, which regulations, when duly promulgated shall have the force of law.