S.C. Code Ann. § 56-5-1015: Lane use control signals.

When lane use control signals are placed over individual lanes the signals shall indicate and apply to drivers of vehicles as follows:

(a) Green indication. Vehicular traffic may travel in any lane over which a green signal is shown.

(b) Steady yellow indication. Vehicular traffic is thereby warned that a lane control change is being made.

(c) Steady red indication. Vehicular traffic shall not enter or travel in any lane over which a red signal is shown.

(d) Flashing yellow indication. Vehicular traffic may use the lane only for the purpose of approaching and making a left turn.