What does a lane use control signal displaying a solid yellow X indicate?

Lane use control signals are used when the direction of the flow of traffic in a specific lane changes throughout the day. They are used to show which lanes of traffic are open and closed, as well as to show if toll booths are open or closed. Drivers should clear the indicated lane when a lane control signal contains a solid yellow X, as the lane signal is about to change to a red X.
DMV Writen Test