What must an airside vehicle do when approaching a runway during operations?

When an airside vehicle approaches a runway during operations, it is paramount that the vehicle waits for direct clearance from air traffic control. This process is essential for maintaining safety on the airfield, as runways are critical areas where aircraft move at high speeds during takeoff and landing. Air traffic control is responsible for coordinating all movements on and near the runway, ensuring that vehicles avoid any potential collisions with aircraft.

Receiving clearance is key; it helps prevent misunderstandings and ensures that all parties have the same information about the airfield's operating conditions. This protocol is part of the overall airside driving regulations and emphasizes the importance of clear communication and procedural adherence in a busy airport environment. Other options, while they may seem relevant, do not align with the established safety protocols required when vehicles interact with runway operations.