Transit-oriented development is not enough

The Washington region is the proud exemplar of transit-oriented development (TOD). Densifying around Metro stations has given us more new homes than other superstar metro regions, keeping our housing prices moderately less inhumane.

Building near the train is fantastic, but insufficient to produce all of the housing we need. According to Up For Growth’s Housing Underproduction Report (which might be a low estimate) the Capital region had a shortage of 156,597 homes in 2019, or 6.5% of the housing stock. To fill the enormous gap, we as advocates need to embrace a “yes, and” mindset. Yes, we should absolutely maximize TOD, and we must also induce political leaders to allow dense housing away from transit.

I believe walkability is the ultimate target urbanists should be aiming at. TOD at Metro stations supports walkability, but is far from the only way to achieve it.

Empirical evidence shows transit plays a surprisingly nuanced role in the places we most associate with walkability. And I have my own doubts from personally living in walkable Alexandria neighborhoods with low traffic congestion and little or no Metro access.

Moreover, Arlington County’s Missing Middle housing debate illustrated how TOD can be distorted into an ideal that NIMBYs and, more consequentially, some elected officials use to argue against building housing away from transit. In other words: against new housing in most places.

The relationship between rail access and driving

Our friends at Smart Growth America define TOD as “investing around existing transit infrastructure.” The US High Speed Rail Association touts “compact, walkable … communities centered around high quality train systems.”

The assumption that rail transit uniquely enables car-lite density is worth examining. “Does TOD Need the T?” asked a 2013 study in the Journal of the American Planning Association. Author Daniel Chatman concluded: not really.

“Auto ownership, commuting, and grocery trip frequency were substantially lower among households living in new housing near rail stations … but rail access does little to explain this fact,” stated Chatman. “Housing type and tenure, local and subregional density, bus service, and particularly … parking availability, play a much more important role.”

UC Berkeley scholar Robert Cervero’s “5 Ds” of VMT (vehicle-miles — or kilometers — traveled) tell a similar story. His analysis of several US studies, summarized below, shows that job accessibility by car alters driving much more (by a coefficient of -0.20) than distance to transit (-0.05) or even household and population density (-0.04). Intersection and street density also has a sizable effect (-0.12) on VMT. Both studies indicate that reducing minimum parking requirements and underpriced parking would significantly reduce VMT.

When rail transit is used to fight housing

Unfortunately, our region’s housing debates do not reflect the complexity of the relationship between housing, transit, and VMT.

Before unanimously enacting Missing Middle housing reform, Arlington County Board members debated how to regulate new multiplexes based on their proximity to Metro stations and primary bus routes. Some worried, for example, that residents of a sixplex in north Arlington might drive.

Missing Middle ended a political grand bargain, struck in the early 1960s, to predominantly limit density to a small radius around Arlington’s Metro stations—the “Bulls Eye” concept. These areas are compact, so compact that some Arlington single-family neighborhoods are walking distance to the Metro. They harbor especially fierce housing opponents.

Setting aside the non-trivial political considerations, the board members’ concerns do not withstand scrutiny. Arlington covers only 26 square miles and is right next to the District. The whole county is, I would gladly argue, an opportunity-rich “transit zone.” It has some of the best cycling infrastructure in the US. North Arlington multiplex residents would otherwise likely live farther from activity centers, and drive much more.

We must continually remind ourselves: Minimizing VMT requires pragmatic tradeoffs. We should help as many people as possible drive less.

Missing Middle opponents eagerly co-opted “build housing near transit” messaging (and yes, many of the same individuals fight TOD). They wanted the perfect to be the enemy of the good. It does not have to be.

Density without Metrorail

The example I usually come back to is Del Ray, Alexandria, where I previously lived (years before Potomac Yard Metro). Its southern edge is within the Braddock Road station’s walkshed, but buses with 30-minute headways are faster than Metro from much of the neighborhood. My experience of Del Ray was defined by gentle density and walkable amenities.

My current neighborhood, Alexandria West, has no Metro access. My family lives in a townhouse abutting Southern Towers, a high-rise complex of 2,346 apartments, right next to I-395. Traffic is never a problem for us, which may have to do with my neighbors, many of whom ride the bus. Alexandria DASH bus service has been setting ridership records.

We should expand TOD too, by aggressively expanding BRT (bus rapid transit). Buses are transit, after all, granting that certain roads are suited to effective bus service. Relatively direct, linear bus corridors such as Arlington’s Columbia Pike have proven to be highly successful, without Metro. Arlington County is currently debating Plan Langston Boulevard, an initiative to upzone along its northern arterial road and improve bus service. Montgomery County’s Thrive plan focuses development along proposed BRT corridors. Expanding bus service entails fairly modest capital investments. Even world-class BRT is orders of magnitude cheaper than rail.

Our region has almost six and a half million residents under a broad definition, which seems appropriate. Some Alexandria firefighters live in Pennsylvania, according to their union, while only six lived within city limits in 2022. Meeting our need for housing requires letting more places away from transit, particularly Metro, grow the way Del Ray, Alexandria West, and Columbia Pike have grown and flourished. Growth should be organic and broad-based, not restricted to either sprawl or concentrated density.

The challenge we face calls for deliberate strategy and long-term thinking. It also demands ambition. Change will be slow, but it has to be big. Huge numbers of people want to live near opportunity and drive less. As urbanists and advocates, we should be open-minded about how to help them, and what good land use looks like.