As a cyclist, being able to cross from Green Park to Hyde Park through Wellington Arch rather than going around the Hyde Park Corner gyratory is pretty wonderful. It's let down somewhat by having to sit in a traffic island half way across to the centre of the roundabout and half away across going off.
I've just discovered that horse-riders have their own traffic lights enabling them to go across in one - but you have to be tall enough to operate the Pegasus crossing button (top right of photo).
With a coach and horses though the coachman isn't able to press the button until his horses are in the motor traffic....so he has a remote control for the lights!!
Any cyclists know where we can get hold of these ;-)