You can see the appeal of their vision, especially in light of the condition of cities they were used to. But instead we got stroads and snout houses for all :/
There's a hand-wavey section about it on Page 18:
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"One of the reasons the traffic jam — with its fretting of nerves and honking of horns — has vanished is that parking in the streets has vanished… Magically you [sic] car has found a place for itself, convenient for you, out of the way of traffic.
Because this central city is planned to do certain things, because space doesn't have to be wasted on things the other cites [sic] do better, there is ample room here… Every office building is on a park and on a parking lot as well.
Every time you put a desk into an office building, you provide space for a car outside. For department store, theaters, the sports arena, and other places where people gather in tremendous numbers, you make special arrangements… underground parking in one place, overhead in another… It can be done… with methodical precision…
Trucking also has almost disappeared from the hub, vast quantities of goods come in, chiefly by boat or train… shoes and food and furniture… motor cars and fountain pens and clocks… for this is the distributing center of the entire area… But the goods are lifted from the boats and the train platform by carriers… and they are distributed by a carrier system to the proper warehouses, and never come into the crowded area."
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They really tell on themselves there with the description of how their ideal community has freight trains but conspicuously not passenger trains, RE: https://www.gothamcenter.org/blog/the-end-of-the-african-ame... for example.
"From 1890 to 1900 the African American population in Manhattan grew by 41 percent from 25,674 to 36,246. Behind these numbers was the growing exodus of blacks from southern states. Seeking to escape racial violence, declining economic opportunities, and legalized segregation, African Americans moved to northern cities like New York in increasing numbers.
A few years after the 1900 riot [in which whites attacked blacks in midtown following the stabbing of an undercover police officer by a black man], as Harlem land values increased with the first subway line nearing completion in 1904, the black residents, once sought as renters in Harlem, became the targets of an organized removal effort by some white Harlem property owners.
The [New York Herald] article also suggested that a rent increase “which the parlor car porters[0] could pay, but their colored inferiors could not,” had previously been used as a strategy to remove the undesirable tenants. According to The Herald, the owners’ target was the “colored inferiors,” but the “wealthy railroad porters” were also caught in the net of the eviction effort."
[0]: https://en.wikipedia.org/wiki/Pullman_porter
See also: when people use the dogwhistle "Manhattenization" to describe city growth as a bad thing.
A lot of things didn't work out but some places seem to have had great urban planning. Particularly - look at that picture of the Estonian city.
https://en.wikipedia.org/wiki/Urban_planning_in_communist_co...
https://digitalrepository.unm.edu/cgi/viewcontent.cgi?articl...