California Vehicle Code Sec. § 21454 When lane use control signals are placed over individual lanes, those signals shall indicate and apply to drivers of vehicles as follows: (a) Green indication: A driver may travel in any lane over which a green signal is shown. (b) Steady yellow indication: A driver is thereby warned that a lane control change is being made. (c) Steady red indication: A driver shall not enter or travel in any lane over which a red signal is shown. (d) Flashing yellow indication: A driver may use the lane only for the purpose of making a left turn to or from the highway.