The City After Cheap Gas

"It's cosmic irony of a sort that the cities most adapted to thrive in 21st-century America may well be our oldest. And those likely to have the toughest time adapting are new – Sun Belt metropolises such as Charlotte, which grew to cityhood in an era of auto travel, air-conditioning and exuberant suburban building.

As I love to do, I spent time last week just walking the old brick sidewalks of this pre-Colonial city across the Charles River from Boston. Although cars make life easier in Cambridge, you don't really need one, and the excellent regional transit system – buses, subways and commuter rail – isn't the only reason. Almost every street has a sidewalk. Cambridge manages to stay bicycle- and pedestrian-friendly despite sometimes heavy traffic. Equally important, there's an old-fashioned mix of stores and housing, so you really can dash out for a loaf of bread or take-out Thai and be home in 10 or 15 minutes. Apartment buildings and houses split into two or three condos sit close together, sprinkled among single-family homes.

Like many older U.S. cities, Cambridge was built in an era when land was treated as precious and wasn't routinely wasted on half-acre lawns or "buffers." It's compact and transit-friendly."