S.C. Code Ann. § 23-6-140

The patrol of the highways of the State and the enforcement of the laws of the State relative to highway traffic, traffic safety, and motor vehicles shall be the primary responsibility of the troopers and officers of the South Carolina Highway Patrol. The troopers and officers of the State Police shall have the primary responsibility for the enforcement of laws relating to commercial motor carriers relating to size, weight, permits, licensing, and inspections for size and weight tolerance and safety. All officers and troopers shall have the same power to serve criminal processes against offenders as sheriffs of the various counties and also the same power as such sheriffs to arrest without warrants and to detain persons found violating or attempting to violate any laws of the State relative to highway traffic, motor vehicles or commercial motor carriers. These officers and troopers shall also have the same power and authority held by deputy sheriffs for the enforcement of the criminal laws of the State.