I love this sort of thing.
On my way home last night at about 9pm the Edgware Road was total chaos. I cross it quite far north, but it was nose to tail in both directions as far as I could see.
The odd thing was that since it was choc-a-block, _all_ the traffic, cars, buses, motorbikes had decided that the lights where I cross over were totally optional. As I was approaching the junction, several hundred yards away, it was green for me, yet all the north and southbound queues were just sailing through the lights.
So it's not just bikes who decide that lights are optional when they feel it is safe and sensible to proceed.
In this case, though, they just ended up in another queue 50 yards up the road.