Here's a slideshow of the Greenbelt Communities, which emerged in the 1930s as part of Roosevelt's New Deal, along with links to some background on the utopian program that built them.
... these three federally built developments combined the suburb’s closeness to nature with the social and economic advantages of cities. built originally for displaced farmers and poor or working families, they encouraged cooperation and community spirit. they also provoked accusations of socialism, and any further developments were stopped after a court ruling declared the federal government’s role in building these developments unconstitutional.
These planned towns didn't set the world on fire--for better or worse--but they have survived, and they serve as links from the early-20th century garden city movement to the contemporary smart growth model. --bds