What must a driver do before entering a runway?

A driver must contact the control tower or airfield authority before entering a runway to ensure that it is safe to do so. This communication is critical to maintain air traffic safety and prevent collisions between aircraft and vehicles on the airfield. The control tower manages the airspace and runway usage, ensuring that all operations are coordinated and that there are no incoming or outgoing flights that could pose a risk. This procedure is established to uphold safety protocols in busy airport environments where timing and coordination are essential for smooth operations.

While the other options play important roles in various operational contexts, they do not directly address the immediate requirement of runway access, which hinges on clear communication with the control tower.