In new city design, high rises shouldn’t just be parts of a city… They need to be the city.
Imagine a building that has electric car paths on all the levels, that have cables to which the electric “cars” attach to for vertical transport. Consisting of many architecturally different designs all melded together, spaces for mini-parks and places of business throughout.
The overall efficiency would excel over the usual American landscape with no need for stop signs and where “everything” is within bicycle (and vertical cable) distance. After being built, the 3-d city would require far less fossil fuels, perhaps even being able to support itself by concentrated solar thermal and other RE (or advanced nuclear if residents would allow). Process heat could then be used to desalinate water.
We still have all the seeds to create a better future, with less congestion, even if the global population was to reach many tens of billions! As long as the ideas are not shredded by big “business as usual”…