ZIPPER markings on airport roads are located on all vehicle service roads that intersect what?

• A. Aircraft taxiways
• B. Runways
• C. Terminal concourses
• D. Perimeter fences

Answer: (A)

ZIPPER markings are used where ground vehicle service roads meet aircraft movement areas, specifically at intersections with taxiways. They guide two approaching streams of traffic to merge in a controlled, alternating fashion so vehicles cross the taxiway safely without blocking each other or interfering with taxiing aircraft. This layout reduces the risk of collisions and keeps service traffic moving smoothly in a high-risk area where aircraft are actively moving.

Vehicles approaching a taxiway crossing use the zipper pattern to take turns entering the crossing, yielding to any aircraft already on the taxiway, and then continuing. That’s why these markings appear on all service roads that intersect taxiways. They wouldn’t be used at runways, terminal concourses, or along perimeter fences, since those areas have different traffic patterns and control needs.