Hill Work

Someone pushing their bicycle up Nine Tree Hill, from the People's Republic of Stokes Croft, Bristol's home of graffiti. There may actually be a Roman road under here; the Romans liked their hill work.
Note the double yellow lines here have no cars on top of them. This is very odd. Two theories:

1. It's too tricky to get to. Certainly you can't do it from Kingsdown, but you can do it from Stoke's Croft.
2. Parking rules are actually enforced here.

You'd have to do some experiments to determine which was correct. Park cars and see what happened.