Today's Inqy has an article about density finally arriving to certain spots out in the 'burbs, after long being blocked by zoning laws. It's important to note that most of the places discussed are early generation suburbs, originally developed around early rail lines, and they already have a slight "urban" feel along the train line and main road route. These are precisely the areas which should've added more density over time, building housing units and expanding retail/commercial districts in areas around train stations.
I'm not unsympathetic to the concerns of existing residents. We can all be NIMBYs. But in the Philadelphia area, at least, there's been a failure to exploit the potential benefit of existing rail routes because of the various barriers to redevelopment.
