Understanding Metro

Prince George’s County has updated its transportation plan to include an extension of Metro’s Green Line to Fort Meade (which, one imagines, would be a step toward its eventually extension to BWI). Matt has some good comments on the plan:

[T]he key thing to keep in mind is that when you’re talking about new heavy rail construction, the potential benefits can be quite large but you have to decide if you actually want to seize them…

If you added a Metro station there, would the local area permit the surrounding quarter mile or so developed as a fairly dense walkable community? Or would people hear about proposals to build on the green space and up-zone the built-up area and decide that would lead to too much traffic? Maybe instead they’ll want to just turn the undeveloped patch into another parking lot. That’d be no good. And the existing land use patterns around Maryland’s Green Line stations don’t inspire a ton of confidence.

To expand on this a little bit, Metro is the region’s most expensive transit option, but it’s also the one with the greatest potential to drive development. Generally speaking, we want to plan our transit systems so that we’re maximizing the benefits we get for the cost of the investment. If Maryland isn’t prepared to zone for significant development around Metro stations, it would be very silly to make the large investment in Metro. Better to develop a commuter rail line or light rail line or both (depending on anticipated development and commuting patterns).

The Silver Line, to take another example, is an expensive investment. It would probably have been much smarter to simply connect Fairfax County destinations (and Dulles) with Arlington and the District via commuter rail but for the fact that the new Metro line is part of a major effort to increase density at Tysons corner. And meanwhile, I think the prospects for development along a circumferential line are significant enough to justify a Metro line, so I’m a little disappointed that the Purple Line will only be light rail (but grateful, of course, that it will be the high-investment light rail option).

For a long time, transit in the Washington area meant Metro, and any area that wanted to improve transit access immediately began pushing for a Metro extension. It’s nice to see alternatives developing, both because Metro investments are often too large to be considered for areas with less development potential, and because lower density areas’ focus on Metro has probably slowed transit investment (which might have moved forward more quickly if areas not suited for heavy rail had instead focused on more appropriate transit options).

One final point: Metro is a network. When a new extension is built, the additional connectivity increases the value of all the other nodes on the system. But while that increase in value is significant, it’s not nearly as great as the benefit conferred on people located along the extension, who suddenly have easy access to the whole of the system. And meanwhile, the usage generated by the extension does generate some direct and indirect costs on other users.

These costs are increasingly borne by users in the core of the system, where growth in the number of trains and passengers have led to crowded conditions on platforms and back-ups during peak periods. To some extent, this can be addressed by increasing peak fares, but given the obvious value of Metro, the growth in the system’s spokes, and the fact that the District is better suited than almost anywhere else in the metro area to handle increased density, it seems clear that new core capacity is needed (as well as a new river crossing over or under the Potomac).

Metro doesn’t stop running when it enters the District. If Virginia and Maryland want to continue to build Metro extensions, they ought to offer their full support to an effort to add capacity in the core.


  1. David Daddio says:

    Only counties zone in Maryland. If existing Prince George’s stations are any example, failure for TOD around metro stops in the suburbs is a combination of NIMBYism, politicking, and WMATA bureaucracy.


  2. Cavan says:

    Well said about the core capacity. I live in Maryland and am sick of hearing proposals for Green Line extensions to BWI and Yellow Line extensions to Fort Belvior. They’re just political footballs and show an utter disdain for the health of the whole system. We need a Blue Line separation in the District long before we need an extension to exurbia.

    Dave’s post did have thought about why to extend the Green Line and he did think about possible places to do TOD. His post was an honest imagining rather than a political football.

    That said, I join the line of people questioning whether Metro would be the most efficient tool to get this job done.

  3. Dean says:

    Has anyone seen a cost estimate for the split Blue Line? I agree that it’s absolutely needed, since the current Blue/Orange lines through the city (and specifically the Rosslyn-FoBo tunnel) are already at capacity for rush hour, but I haven’t seen anything concrete. I’d be interested to hear about practical concerns like geography or station siting.

  4. Steve Teles says:

    I honestly think that extending the green line to BWI is sort of nuts. It probably makes more sense to add capacity on MARC, esp. by adding more express trains, and have it run more frequently (including on weekends). Most trains from Baltimore to DC (I take one at least once a week) on MARC take almost an hour, but the fastest one takes only 35 minutes. If you had regular 35 minute trains from Baltimore to DC, that would do more than almost anything to integrate the two cities (and would be great for Baltimore).

  5. Cavan said: “We need a Blue Line separation in the District long before we need an extension to exurbia.”

    Agreed, but it ain’t gonna happen that way, and we all know it.

    I don’t know if the way WMATA is organized allows DC to throw any roadblocks in the way of new lines in exurbia, but if it does, then it ought to use those roadblocks to demand suburban aid in funding an expansion of core capacity simultaneously with the construction of these far-flung lines.

    I’d say that’s the best we can possibly expect, and even that’s dependent on some big ‘ifs’.

  6. jim says:

    Steve Teles gets it exactly right. Before anyone starts talking about extending Metro, beef up MARC. MARC all day. MARC through the evening. MARC on weekends. Get MARC hours up to Metro hours. Run MARC through into Virginia. If, after that, there’s still a need for additional transit capacity in PG, consider extending Metro (along with considering cheaper options like light rail feeders to MARC).

  7. Alex B. says:

    Absolutely. If we can get MARC service (and commuter rail in general here in DC) up to the level of service you find on many of New York’s lines, we’d be set.

    For the expressed purpose of serving Fort Meade, you’d get the bonus of having high levels of service from both DC and Baltimore.

    I noted in my response that the Silver line is different – there is no other existing transit corridor along the Silver line. Also, there’s not a major center like Tysons begging for service. Despite Fort Meade’s impressive employment concentration, it will never be built up as private land is – even if it were to take an autocentric form, like Tysons.