Grow Smart Planet has identified 27 regions with a total population of 38.6 million that are large enough to support regional rail transit systems with crosstown feeder bus routes. Most of them have no rail lines or just a short “starter” rail line now. Many other regions have rail transit lines serving several areas, but are considering extensions or crosstown routes that remain unfunded. We anticipate many regions will be able to “take the ball and run with it” without spending a fortune on costly planning and engineering consultants. This will be easier if they have a copy of Sustainable Transportation and Development and get the right people to read it.