What signals the driver to return to the starting point?

The flashing white light is the correct signal for the driver to return to the starting point. In air transportation operations, particularly in air traffic control and airport ground handling, signaling systems are established to promote safety and coordination among drivers and aircraft. A flashing white light typically indicates that it is safe for the driver to proceed or that specific actions should be taken, which, in this case, relates to returning to the initial location.

The other signals mentioned have different meanings in this context. A steady green light typically indicates that the driver is cleared to proceed, while a flashing red light often warns of danger or indicates that the driver should stop. A steady red light usually signifies that the driver must remain halted and not proceed further. Understanding these signals is crucial for maintaining safe and efficient operations in an air transportation environment.