Section 21454 Of Article 3. Offenses Relating To Traffic Devices From California Vehicle Code >> Division 11. >> Chapter 2. >> Article 3.

. 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.