One of the projects I have on my (very) back burner is to do an historical timeline of the development of Bristol bus routes. I think that might even be how this thread got so extended! I am interested how social and economic change led to the introduction of services and their subsequent modifications. For example, up until the 1960s half of the bus services went via Old Market and the other half via The Centre, reflecting the former importance of Old Market and its subsequent decline.The #2 route in those days turned around in that location and was probably one of the first cross city route.
I am gradually piecing together information when I have five minutes here and there, so any recollections are very welcome!
There are some excellent books about Bristol Omnibus, but most concentrate on the vehicles rather than the routes and commercial / operating side of things. Maybe I shall be the first to eventually come up with a book on this extensive subject!