Here is how I see American cities at the middle of the 21st century:
Because of high energy costs, living on large lots in the exurbs will no longer be affordable to the middle class. New policies will go into affect that support infill development in older city centers. As the populations of central cities grows again this will put a strain on already fragile infrastructure. Cities will begin rebuilding mass transit systems they ripped out long ago in favor of the car. People will still have cars but better mass transit along with walkable communities will make driving less mandatory and more affordable.
Gentrification has continued its insatiable march forward. Areas that were once hip are now populated by the middle classes with large new apartment buildings going up where fancy condos once were (and before that vacant lots and burned out buildings). Areas that are today considered the ghetto will be the new hip places where artists and YUPies mingle. The poor that once filled these streets will have been pushed further out into once middle class suburbs.
This will not have come easy. Much like the riots that flamed white flight in the 1960s, new class riots will erupt as the inner city poor feel the pressures of a society that they cannot afford to live in while being pushed out by much wealthier whites. Riots and demonstrations will ensue, and while the city will call calm and understanding, behind closed doors the elites will be helping move the poor out so real estate developers can move in.
This new rebirth of the city will mean that there will finally be political pressure put on restoring streetcars and building new subway lines. Because the poor will have been forced out into the suburbs, where rail service is few and far between, new Bus Rapid Transit lanes will appear on highways. Highways were once crushed with traffic can now afford to lose a lane for the only mass transit available for suburbs.
Suburbs will not die. Though the once urban poor will have moved in, many middle class and wealthy people will still be able to afford living there and will prefer it. Large lots will let people have small farms, usually tended by a local farm company so the residents don’t have to do the work themselves. Most suburbs will have created town centers, much like the old main streets, where residents can walk to. These centers will allow for bus and light rail transit to shuttle residents into the city or to a commuter rail station near by. Because of the class differences, gated communities will be the norm, even more than now.
The children who today are not yet born will become the artists that reclaim the abandoned edge cities of the future. Our massive malls today will be abandoned when energy costs make them unsustainable. Most will be left to decay as the suburbanity around them will be given up. As the inner cities looked to Americans in the 1970s and 1980s, so too will these edge cities look in the near future. But this is exactly the type of place young artists and rebels need to grow and create. Malls will become the new loft spaces. Communities will grow where consumers once walked past retail stores. The massive parking lots, already over grown, will be turned into collective farms. The large roofs will be used for water collection and solar energy. Malls, once symbols of everything wrong with the culture of mass consumption, will be turned into the very ideal of sustainable communities. This lays the ground work for the gentrification of the suburbs in the next 50 years.
High Speed Rail has replaced air travel as the preferred means of getting from cities that are close to one another. Air travel will still be available but will be supported by the government and will only fly long distances or in certain corridors with large amounts of traffic (i.e. Northeast Corridor). Many of the new rail lines will have been built, or are being built, along medians of highways since the land is already owned by the states and the rebuilding of central cities has meant land prices have increased to the point where eminent domain is not as affordable, nor as popular, and option.