Photo by KristonRehberg on Flickr.

Congressman Gerry Connolly and local officials are holding a public meeting September 26 in Prince William County to discuss extending Metro to Woodbridge.

It this a good idea? Like any proposal, it has pros and cons. The issue also depends greatly on whether you look at the problem from a transit planner lens or a public opinion lens.

Is actually bringing Metro to Woodbridge a good idea? If money were no object, probably. However, it would worsen capacity crunches in the core, and so really needs to be paired with a project like the separated Blue Line or separated Yellow Line in DC.

Is bringing Metro to Woodbridge worth the money? It depends what else you spend the money on, but if the same money went to other transit, expanding VRE and express bus options is probably better. However, the budgetary tradeoff is rarely between Metro and other transit of equivalent cost.

Is talking about bringing Metro to Woodbridge a good idea? Absolutely, because talking about how transit can best serve the people of Prince William County can only lead to better thinking about how to grow the Woodbridge area and general public support for transit. Besides, most likely if the state isn’t planning a Metro extension, it would instead be planning some much more sprawl-inducing highway proposal.

First, let’s talk about the actual tradeoffs in serving the area with transit.

Any Metro extension in this area absolutely has to serve Fort Belvoir. This is the largest focused job center in the area thanks to BRAC and will likely continue to grow. Putting any new transit here without going to Fort Belvoir would be foolish.

In particular, one factor that makes Metro much more cost-effective than other transit systems which serve suburbs, like BART, is the way Metro has significant reverse commuters. Instead of mostly empty trains out to the ends of lines in the morning, many people are riding those trains to federal facilities like those at Medical Center and Suitland.

There’s already been talk about extending the Yellow Line down Route 1 instead of the Blue Line. This has the added benefit of helping the communities along the way, many of which are just the kind that could plan constructively around transit. Just like the Rosslyn-Ballston corridor 30 years ago, there are aging and often struggling commercial properties which could become mixed-used transit-oriented communities serving people who work to the south in Fort Belvoir or to the north in Alexandria, Arlington and DC.

Image from Fairfax County.

Building any new rail line, however, is quite expensive. Most of the area is low density. Meanwhile, there’s another rail line already here: VRE, which goes to Woodbridge (and has a station not far from Fort Belvoir).

Why not make VRE run far more frequently? It could even combine with MARC to create Metro “express lines.” With fewer stops, these would provide a quicker route to the Pentagon and downtown than any Blue or Yellow line extension would.

The biggest obstacle is that VRE doesn’t own the tracks, which also serve as the primary east coast freight line. CSX is planning to run even more freight here, which is why they’re expanding the tunnels on Capitol Hill as part of the National Corridor plan.

The freight trains don’t necessarily need to go through downtown DC. In fact, it’s probably better if hazardous material weren’t being transported a few hundred feet from the Capitol. NCPC looked years ago at adding a freight bypass, but it’s expensive and encountered political opposition in Southern Maryland.

Image from NCPC.

Without building the freight bypass, Virginia could still improve capacity on the VRE Fredericksburg Line by adding passing tracks and a third track as much as possible. Some of that is already happening to accommodate more Amtrak service. Plus, improving this line can enhance intercity rail to Richmond.

Any added Metro service would increase the numbers of passengers coming into the central sections of the Metro system (Arlington and DC). As that ridership grows Metro will need to run the maximum possible numbers of trains on the Blue-Yellow segment, but to do that, they’ll need one of the core expansion projects to separate lines.

That’s either a new M Street Blue Line subway from Rosslyn to Georgetown to downtown, so the Blue Line trains don’t have to merge with Orange and Silver trains at Rosslyn, or a separate Yellow Line tunnel from Southwest to either downtown or Union Station, so Yellow Line trains don’t have to merge with Green at L’Enfant Plaza.

The other option is more express buses. Virginia has looked at projects which add special bus exits on and off the freeways, so buses can run in HOV or HOT lanes, get off and stop at a station near the freeway, then hop back on. Light rail could also serve the corridor.

These options are far cheaper. If the tens of billions of dollars required for such a project were sitting in a special bank account marked “TO BE USED FOR TRANSIT IN SOUTHERN FAIRFAX AND EASTERN PRINCE WILLIAM,” then a combination of buses and light rail is likely the most productive use of the money. However, that’s never the way it works, and planning a big transit project may be the best option compared to the likely alternative, which is planning big and destructive highway projects.

In the next part, we’ll talk about the political and public opinion ramifications of talking about such a project.

David Alpert is Founder and President of Greater Greater Washington and Executive Director of DC Sustainable Transportation (DCST). He worked as a Product Manager for Google for six years and has lived in the Boston, San Francisco, and New York metro areas in addition to Washington, DC. He lives with his wife and two children in Dupont Circle. Unless otherwise noted, opinions in his GGWash posts are his and not the official views of GGWash or DCST.