When lane use control signals are placed over individual lanes, said signals shall indicate and apply to drivers of vehicles as follows: 1. Green indication - Vehicular traffic may travel in any lane over which a green signal is shown; 2. Steady yellow indication - Vehicular traffic is thereby warned that a lane control change is being made; 3. Steady red indication - Vehicular traffic shall not enter or travel in any lane over which a red signal is shown; and 4. Flashing yellow indication - Vehicular traffic may use the lane only for the purpose of approaching and making a left turn. Laws 1977 c. 21, § 2, emerg. eff. April 15, 1977.