Wired's Autopia blog takes a look at the rise of urban populations and the challenges faces some smaller cities as they try to put transit systems in place.
"Such growth is not as big a concern for cities with extensive multi-modal transit systems. But what about cities that don't have the extensive transportation networks of, say, the Big Apple? This question takes on added urgency when you realize that more than 400 million people will live in the United States by 2050, with a majority moving into more urbanized parts of the United States breathing revitalization to once depressed cities, while creating new ones.
Clearly we must look to our transportation systems as the basis, or, to use a biological metaphor, the the connective tissue for new urban development. This will allow us to continue the trend toward urban living while providing public transportation options the public wants - and, increasingly will need."