The author's reference city has districts arranged in 81 circles with a radius of 380 meters around metro stations on 1 of 3 metro lines. The reference city is supposed to be able to house about 1 million people. His predicted maximum travel time is 35 minutes from one side of the city to the other.
He came up with the idea of a metropolitan area of 6 of these cities linked by a 200km/hr (124mi/hr) train. The maximum transit time in that system was 50 minutes, though it did require up to 3 transfers instead of the 1 required by the other city design.
I thought LA county would probably be well served by such a system, though I was off by a little over a third, there's actually 9.8 million people living in LA county. But still (for those who live in LA), imagine going from Canoga Park to long beach in a guaranteed hour.
The other idea is I can't really influence Los Angeles as a whole to move more toward a car free world, however possibly the city I live in, Pasadena, could perhaps be convinced to experiment with this.
Pasadena has it's own rich culture, museums, theaters, restaurants, architecture, etc. Property prices are climbing higher than most can afford. Nearly 40% of the residents of Pasadena work in Pasadena. There's a large tradition of really irritating traffic calming measures. There's even going to be an electrified rail running through Pasadena in the near future. There's a good array of mature trees.
All in all Pasadena might provide a much better area to target to try and move cars out of the city and off to the periphery than most other portions of the LA metropolitan area.
Oh yes, not only are travel times lower in his example design than current traffic-congested cities, there's even far, far more open space.
The cost for these carfree cities is needing to be willing to walk up to 5 minutes to go from the periphery of a district to the central metro station at each end of your destination. (Obviously less walking if the starting or ending points are closer to the metro station.) And being willing to stash ones car off in a parking structure at the edge of the city.