Okla. Stat. tit. 47, § 47-11-204.1: Lane use control signals

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.