Botswana Meat Commission FC says: "I dig all the talk about transportation/transit around here. How about some analysis of light rail and 'express bus' options that are sort of a halfway point between city buses and heavy rail." A few points on this.

As a mainline transit option, the great virtue of bus routes is that they're easy to set up. In ideal circumstances, I think the service on Georgia Avenue currently provided by the 79 Express Bus line in DC should be a full-fledged Metro line. There could be a separated Yellow Line extending north from the Shaw/Howard station along Georgia Avenue with transfers to the Green Line at Petworth and to the Red Line at Silver Spring. But that would be very expensive, wouldn't really be my first priority for expensive projects, and would take a long time to finish. So the 79 is a solid, practical solution. But by the same token that bus lines are easy to set up, they're easy to shut down and it's very easy to shift the stations around and consequently they aren't going to do a good job of becoming a locus of private sector investment and altered development patterns. A light rail line can do more to create dense hubs around stations with a vibrant commercial corridor running between them.

The choice between a light rail and heavy rail line, ideally, ought to be made not on the basis of the fact that the light rail line is cheaper but by thinking about what it is you're trying to accomplish. Light rail doesn't move as many people and, consequently, can't serve as the transportation backbone for as dense an area. But maybe you don't want to build a super-dense area, but you do want to have a workable transit link. Light rail's a good solution.

Across an entire metro area, you should expect the transportation network to genuinely be a network that involves heavy rail on some routes, light rail or BRT on some others, and then probably various kinds of local bus routes that work for shorter trips or bring people to hubs for other transportation modes. If you look at the best transit cities in Europe, you'll see that they have all kinds of stuff going on in terms of light rail and subways and commuter rail and intercity rail and buses all on top of each other.

Photo by Flickr user Intangible Arts used under a Creative Commons license

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