Masdar City is an experiment around Dubai where all cars are underground, top level is pedestrian. They built it from scratch so they had that luxury.

http://www.masdarcity.ae/en/ http://en.wikipedia.org/wiki/Masdar_City http://www.youtube.com/watch?v=PB_5TBZQNRY

Also the cars are automated - self driving. They don't have to deal with pedestrians and traffic, so much easier to automate driving.