I just came up with a thought the other day! This would be a decades long approach and I have no idea if it would work. The idea is for generic American cities, that have a few sky scrapers in a downtown and then the burbs.

I should add:

• transit costs are expensive. Build them in at the start
• look at the "15-min city" concept.
• look at "mixed-use (high-density) residential"

I live in an area of mixed-use high-density and it's done really well: I use the train for everything thats not immediately close-by, all my daily stuff is within a block or two, I've rarely driven in 5 years, and while I know the 30-storey buildings above the shops are 97% occupied, I really don't notice the neighbours.

It's segregated, rez and biz, but I showed my neighbor how to cope. Now her commute with her kids to daycare is 1 elevator, switch at P4 to the other elevator stack because they both come out in the same room, go back up to the daycare at G to drop the kids off, and walk out to the mètro. Her kids' commutes are dry, warm and safe, and they're safely away before she leaves the building.