Some of the free market attempts in the UK ended up with Milton Keynes which is pretty much the American auto style roads come first. While others ended up with

Some of the free market attempts in the UK ended up with Milton Keynes which is pretty much the American auto style roads come first. While others ended up with city of London which is highly walkable and dense being just over a square mile. Cost of land and transit is probably the deciding factors for the free market. Conversely regulation has given more walkable areas (mixed zones, offices, and small retail on the street with residental) so it's not just a case of the amount of regulation but what they say.