As I wrote yesterday, I don't know Phoenix and have no idea if the new light rail project there makes much sense, but I do know that such projects in places like Phoenix are much more likely to be good ideas if it's understood that development patterns around the rail line should change. It isn't enough to simply say that another way to go from A to B has been created, it should be understood that development, and lifestyle, around the rail line should, over time, evolve to better make use of it. According
to this article, there's at least some thinking along those lines.