Dave Murphy has an insightful article on the Greater Greatter Washington blog criticizing the Central Maryland Transportation Alliance's call to jump the Towson-Columbia Yellow Line ahead of a northeastern extension of the existing Metro subway (Green Line).
Briefly, Murphy questions the usefulness of the southern part of the proposed Yellow Line between Columbia and BWI. As much as I like the idea of rail transit serving my neighborhood -- not that I'd still be mobile by the time it's built -- he might have a point there. Columbia could probably be served faster and more economically with the creation of an express bus route between the BWI Business District light rail station and Columbia Town Center. That would be about a 30-minute run on Route 100. If the light rail and bus schedules were properly synchronized, that could be a robust transit alternative that wouldn't have to wait decades to become a reality.
Howard Transit's Silver Line already makes the BWI-Columbia run but its many stops make for a long, long trip. An express version of that route would increase the usefulness of the entire system.