Dual cycle network: link here to map showing "The main roads – in red – form the basis of the main cycle routes, typically using bus or cycle lanes. The quiet routes – in blue – make a connected network for those who want or need to avoid traffic."
the thing is those red roads are BIG roads for oxford, the equiv of dalkeith road/lothian/morningside etc. they have a lot of buses and go past where most people work in the city centre, the unis, the publishers, the schools and the train station. But what is different from edinburgh is that there is almost no parking in the city centre. If you go to visit OUP, for example, they will not tell you where to park. When we stayed recently at the University Club they make it very clear that they have no parking, except for disabled visitors - and this was a condition of their recent expansion and development.
Here is more of a discussion. some salient points : "Parking on main roads has mostly been removed".."The bus lanes (and bus priority lights) mean that buses get significant priority over cars. "..."political acceptance that car-access can be actively discouraged [because of good bus service], to the point that there are considerably fewer cars on the main roads than you might expect.".
We have the good bus service here, but NOT the political acceptance to limiting car use.