[jordanthoms]

My fantasy is to build a city with lots of roads, but put them underground. Street level can be solely for pedestrians, bikes, and vehicles delivering things on that block (although most buildings would have underground road access).

[justincormack]

London tried to have a form of that, where pedestrians could go on raised walkways, while the cars owned the roads underneath. Fragments remain around the Barbican in the City of London, and you can see blocked off unfinished walkways.

Underground roads are being suggested in many places as they free up land for buildings.

[vidarh]

Toronto is a better example of separating cars and pedestrians, though it's underground rather than raised:

http://www1.toronto.ca/wps/portal/contentonly?vgnextoid=f537...

[Nicholas_C]

Dallas recently built a park[0] over a highway smack dab in the middle of the city and it has been a huge success. It would be great to do this in more places.

[0] http://www.klydewarrenpark.org/