Aren't traffic lights in built-up areas meant to be synchronised, so the junction-to-junction time is about the time it takes for the next lights to turn green? In which case, someone was obviously expecting everyone to be doing 70 down Broadway.

Generally, yes they should be. But unfortunatly around here, they forget to even bother checking the lights when they are replaced. Thus, I sit through 3.5 red lights on average (out of 4) on a mile stretch off the highway when going home.