Urban dispersal is one of the more bizarre proposals for restructuring society to cope with the threat of nuclear war that circulated in the late 40s and early 50s. Sociologists and urban planners, mostly notably William Ogburn, seriously proposed breaking up our large cities and turning the country into one gigantic suburb, so as to eliminate potential targets of nuclear attack. Your challenge is to have this actually happen with a PoD after the 1945 Trinity test. Bonus points for achieving this without the use of WMDs beyond what happened IOTL.