Well, then the Americans will have to return to public transportation like trains, tramways, buses, subways etc as they used to have in the past.
And to give up Mac Mansions and sprawled suburbs. Can be done. Horses in rural areas will not hurt either :)
You think that people will give up their big houses and move into cities? REALLY? And just WHERE are they going to find city housing? There is a dearth of empty places in just about every major city in this nation.