When must vehicles come to a complete stop on the airfield?

Vehicles must come to a complete stop on the airfield at stop signs, hold lines, and when directed by air traffic control because these situations are critical for maintaining safety and proper traffic flow within the airfield environment. Stop signs are placed to indicate where a driver must yield to any oncoming aircraft or other vehicles. Hold lines are designated to ensure that vehicles do not encroach upon runways or taxiways without clearance, which is essential for preventing accidents. Additionally, adhering to directives from air traffic control is crucial, as these professionals monitor ground and air traffic to ensure safe operations. Ignoring these protocols can lead to dangerous situations on the airfield. Therefore, a complete stop in these circumstances is a fundamental safety measure for everyone involved in airfield operations.