Are there different rules for trucks that only operate within South Carolina versus those that cross state lines?

Trucks that cross state lines (interstate commerce) are subject to the full scope of federal FMCSA regulations. Trucks that operate exclusively within South Carolina (intrastate commerce) are primarily governed by state law, but South Carolina has adopted most of the federal safety regulations as its own. Therefore, the same critical safety rules regarding driver hours, vehicle maintenance, and safe operation generally apply to all large commercial trucks on South Carolina roads.