What indicates to drivers that they can exit their vans and find their route in the station?

The correct choice indicates that the signal given by the Yard Marshal serves as a clear and direct communication to drivers about when it is appropriate for them to exit their vehicles and proceed to find their route within the station. This is crucial for maintaining an organized and efficient loading and unloading process, as the Yard Marshal is responsible for managing the flow of vehicles and ensuring safety in the area.

The Yard Marshal typically has a strategic view of the yard, allowing them to oversee vehicular movements and communicate when conditions are optimal for drivers to disembark. Their signal can provide immediate and visible guidance, helping to streamline operations and prevent confusion or accidents.

In contrast, while route sign displays, radio announcements, and light signals can also provide important information, they may not be as precise or immediate as the direct action taken by a Yard Marshal. The signs might inform about routes generally, radio announcements may not be synchronized with the actual moment of departure, and light signals could be affected by visibility issues or misinterpretation. The Yard Marshal's role is specifically designed to address the timing and safety aspects of drivers exiting their vans effectively.