With Rail~volution complete, several recaps of conference sessions have sparked some interesting discussion.  One panel posed the hypothetical question – what would DC look like today if we had never built Metro?

WMATA’s Nat Bottigheimer emphasized the linkage between high capacity rapid transit and the ability to support dense urban development, drawing a contrast to the spatial inefficiency of automobile-based systems:

Bottigheimer gave an analogue for Washington, DC, saying that the parking needed to serve all the cars that would come in place of Metro could fill the entire area from 12th to 23rd Streets, Constitution to R (including the White House) with 5-story parking decks.

That’s a lot pf parking.  It’s an absurd amount, really – but it shouldn’t be a surprise.  Consider an auto-oriented business district like Tysons Corner:

Tysons’ dependence on the automobile, and a place to park it, is dramatic when compared with other areas. With about 120,000 jobs, Tysons features nearly half again as many parking spots in structures, underground and in surface lots. That’s more parking, 40 million square feet, than office space, 28 million square feet. Tysons boasts more spaces, 167,000, than downtown Washington, 50,000, which has more than twice as many jobs.

Of course, downtown DC never would’ve developed in such a fashion.  Bottigheimer’s hypothetical is meant to draw a contrast rather than represent a plausible alternate universe.  Never the less, the ratio of space devoted to parking compared to space devoted to other stuff (offices, retail, housing, etc) is striking.  An auto-based transportation system requires the devotion of half of your space to just the terminal capacity for the car.

While acknowledging Metro’s power to shape development and growth when paired with appropriate land use and economic development policies, the GGW discussion turned (as it often does) to Metro’s constraints.  Several commenters ask – why not four tracks like New York?  Why not have express service?

Sample of Midtown Manhattan track maps from nycsubway.org

New York’s four-track trunk lines are indeed impressive pieces of infrastructure, but it’s worth remembering that they are essentially the second system of rapid transit in the city.  New York did not build those four-track lines from scratch, they built them to replace an extensive network of elevated trains. Consider the changes from 1904 (left), to 1932 (center), to present (right):

Red lines are elevateds, blue lines are subways – source images from Wikipedia. The process of replacing older elevated trains with subways is clear, particularly in Manhattan and around Downtown Brooklyn. The relevance to DC is that four-track subway lines don’t just happen.  The circumstances in New York that desired to get rid of most of the elevated tracks provided an opportunity to rebuild all of New York’s transit infrastructure.  Metro is not provided with such an opportunity.  Adding express tracks to the existing system would require essentially rebuilding the entire system, and without a compelling reason to do so (such as New York’s removal of Els), it’s simply not going to happen – no matter if it were a good idea and a cost-effective idea or not.

Perhaps the single biggest opportunity for an express level of service would be the conversion of MARC and VRE into a through-running S-Bahn-like transit service. Portions of the Red Line do indeed have four tracks – its just that two of them are for freight and commuter rail.  Likewise, should there be future expansion of Metro within the core (such as a separated Blue line) there would be the opportunity to study making such a tunnel a four-track line.  That concept would have to include a number of different ideas, however – future expansions to link into that capacity, surface/subway hybrid service for streetcar (such as in Philadelphia or San Francisco), etc.