I recently discovered the Carfree Cities website, and feel a little bit foolish for having bought the Carfree Cities book, because I think the web actually tells the story better than the book. I suppose that I'm paying for the cost of the site, so that's not too bad.
J.H. Crawford is entirely serious in proposing that a city of a million people or more can function entirely without cars or trucks. My own image of utopian urbanism — setting aside my dreams of arcologies — has long excluded private cars but included taxis and trucks. Crawford has convinced me that these aren't necessary, that a truly carfree city is possible. After all, observes Crawford, Venice manages just fine without cars, and this helps to make it arguably the most pleasant city in the world.
Crawford's argument is, in fact, full of surprises. There's some crafty number-crunching that shows that in principle a city of a million inhabitants could be structured with 80% green space, four-story buildings, and a metro system that takes people from anywhere to anywhere in no more than 35 minutes, with no more than a 5 minute walk at either end. The metro system in Crawford's reference design is very cunning: there are only three lines, and everything is reachable with a single transfer.
Part of the trick is discussed in the book: most folks don't understand which parts of the public transit system to optimize. Where does the time go? Train accelleration is not so important, but designing the doors to start opening a moment before a train stops cumulatively shaves more significant time off of a long trip. There's a lot of good, deep thinking like this in Crawford's proposal.
The website also includes a fun pattern language of good stuff to have in a city, very much taking after Christopher Alexander. Crawford is a fan of a Mediterranean model: open courtyards in the centers of blocks, twisty little streets, arcades, little squares, and so forth.
Oh, and he wants to convert the interstate highways system into rail, too. My kind of guy.