What is the purpose of runway guard lights and when are they used?

• A. Flashing amber lights at runway/taxiway intersections to warn pilots and ground vehicles of potential runway crossing hazards.
• B. Green steady lights indicating runway clearance for takeoff.
• C. Red lights indicating a runway closure.
• D. Blue lights guiding aircraft on taxiways.

Answer: (A)

Runway guard lights are an alerting system at taxiway/runway intersections designed to prevent runway incursions. The amber lights flash to draw attention to the boundary where a taxiway meets a runway, warning both pilots taxiing near the intersection and ground vehicles that a runway may be in use or may be crossed. They provide a clear visual cue that extra caution is needed before entering or crossing the runway, supplementing other hold-short markings and ATC instructions. They are not used to indicate takeoff clearance (that involves green lighting concepts), not to signal a runway closure with red lights, and not to guide aircraft on taxiways (that role belongs to blue taxiway lighting).