...sprawl is self-limiting because who wants to do a 4 hour daily commute? Not in the larger scheme of things. People move to suburb X before grid lock and hav

...sprawl is self-limiting because who wants to do a 4 hour daily commute? Not in the larger scheme of things. People move to suburb X before grid lock and have a one hour commute. Enough people move there that the commute is suddenly two and a half hours or more. But people keep moving to the area because the houses exist, the land is still relatively cheap and so-forth. The bottom may even fall out of the market but the place exists, someone will buy the houses. Exurbs can easily become suburban ghettos like Antioch or Modesto. But naturally, it's not just the commute part the closes in on exurbs. Cost of services is higher and once the places become less-than-upper-middle-class, they don't have a tax base to pay for expensive services, they become less desirable than urban ghettos.