You'd need a lot of exit ramps going up though, and it would be pretty tricky for emergency services to reach the places they need to go to. Personally I'm a big fan of reducing through traffic as much as possible and banning vehicles other than for the disabled and emergency services from city cores.
> We could have big houses, with windows that shutter in the summer mornings to keep out every bit of the too-early light of dawn, or shutter in the night to leave the stars absolutely untouched. We could have roofs that let in the sun.