Though it seems most are ignoring the signs, you do have to wonder why they don't technically allow cyclists to use this bit of Princes Street.
Missed opportunity by blackpuddinonnabike, on Flickr
It's an 'emergency' lane. Though today it was also blocked off as railings were moved to allow a works truck to deposit a load. I'm pretty certain that's more difficult to move out of the way of an ambulance than a bike...