How is a taxiway junction lit?

A taxiway junction is the point where two or more taxiways meet — a T-junction, an angled (Y) junction or a cross. The lighting has to answer three questions at once: what shape is the pavement, which routes can I follow, and where might I be required to hold. Each question is answered by a different system, and the junction is where they overlap. For the full layered picture see Entry 8 · Taxiway Intersection Lighting.

1Edge lights outline the pavement

Blue edge lights follow the full outline of the pavement, including the rounded corner fillets where the branch opens onto the through taxiway. On those curves spacing is closer than 60 m, as on any taxiway curve (see Entry 24 · Taxiway Edge-Light Arrangement). Annex 14 also requires that edge lights at an intersection, exit or curve are shielded as far as practicable, so they cannot be seen from angles where they might be confused with other lights.

2Centreline lights carry each route

Green centreline lights do not stop at the junction. The through route runs straight on, and each branch route curves off tangent to it, so a pilot always has one continuous line to follow for the route they have been cleared to take. Spacing on the branch curves tightens with radius — see Entry 18 · Taxiway Centreline Configuration.

3Holding is added on top

Where ATC needs traffic to wait before a junction, yellow holding-position lighting is added to the base layer — a clearance bar (Entry 12) or intermediate holding-position lights (Entry 13). The matching marking is set across the taxiway at a sufficient distance from the near edge of the intersecting taxiway to keep taxiing aircraft safely apart, so the bar sits before the junction rather than inside it. Where the junction meets a runway, a stop bar can be used instead (it is required at runway holding positions for operations below RVR 350 m), interlocked so that the centreline lights beyond it are switched off while it is lit.