Yes, indeed, there are a lot of pixel lights. We are using deferred rendering, there aren't too many light overlaps, and also no point light shadows, so it is quite efficient. There is no special activation of lights, they get spawned together with walkways, but since in deferred rendering it only matters how many pixels on screen one light covers, rendering distant lights is actually very cheap. Btw, runway lights are just bloomy billboards, not true lights.