McMillan isn’t next to Metro, which is less of a problem than you think

McMillan Reservoir

You can see the Capitol Dome from here. Photo by Eric Fidler, via Flickr

Yes, the McMillan Sand Filtration Site is one mile (from either end of the site) to the Red Line. It’s even 0.6 miles to the nearest express bus route (Georgia Avenue’s 79), and key network improvements are still in the planning stages. Yet from the point of view of someone who wants to reduce auto dependence (and the concomitant pollution, injury, and sprawl), what matters most is that MSFS is close to downtown, rather than close to Metro.

Transportation planning research has consistently shown that location relative to downtown and to other land uses is far more closely associated with the amount of driving than location relative to transit. Ewing and Cervero’s definitive 2010 meta-analysis (cited by 679 other scholarly articles) examined over 200 other studies, then combined the correlations found by 62 different studies:

Yes, it turns out that the number of miles that people drive is four-and-a-half times as closely correlated with the distance to downtown than with the distance to a transit stop. This strong relationship between driving and distance to downtown is borne out in local survey research by MWCOG/TPB. Note that whether an area has Metro access (like Largo or White Flint, vs. the Purple Line corridor) doesn’t actually seem to impact the number of drive-alone (SOV) trips.

Some suggest that development proposed for this site should instead go elsewhere. If the development is denied, those residents and employees and shoppers won’t just disappear, they’ll just go somewhere else. They won’t go to superior locations even closer to downtown and Metro (because those are so very plentiful!), but rather to far inferior locations. For instance, the life-sciences employers might choose an alternative location within our region that has already approved a similar mix of uses — such as Viva White Oak, Inova Fairfax, Great Seneca Science Corridor, and University Center in Ashburn, all of which are much further from both downtown and Metro.

This isn’t just the suburbs’ fault. Within the District, even more intensive development than what’s proposed at MSFS has already been given the go-ahead at locations such as the Armed Forces Retirement Home, Hecht Warehouse, and Buzzard Point. All of those sites are also inferior to MSFS from the standpoint of not just transit accessibility and distance to Metro Center, but also on all of the other factors shown to reduce VMT.

If the “Reasonable Development” types truly do care about reducing driving, I must have missed their years of caterwauling over the approval of all these other sites — not to mention the countless suburban developments that together pave over 100 acres of open space every single day in the Chesapeake Bay watershed. That’s why I give more credence to the people who do actually care about paving over the region, like the Piedmont Environmental Council — a/k/a the Coalition for Smarter Growth.

Friday photo: Build in town, not edge towns, to cut carbon

edge town

The results are definitively in: when it comes to cutting carbon pollution from new development, location is far and away the most important factor. Even bad infill development will easily beat even the best greenfield design in terms of avoiding car trips — the single most climate-damaging activity in most Americans’ daily lives.

Kaid Benfield illustrates the point by contrasting the VMT per capita within some of the best suburban and urban neighborhood designs of recent years. Grounding his analysis in research, he writes:

[L]ocation is by far the most significant indicator of how much driving typically takes place to and from a given neighborhood. This is because of something called “destination accessibility”: outlying locations have fewer jobs, shopping opportunities, schools and other typical trip destinations within easy reach than do more central locations, causing average driving distances to be longer. (It is also generally easier in more central locations to substitute transit and walking for what would otherwise be driving trips, but such “mode shifts” are statistically less significant to vehicle miles traveled than are driving trip distances.) As a result, carbon emissions from outlying locations, per person and per household, tend to be higher – typically a lot higher – than those from closer-in locations.

It takes a lot of effort to create new “connected, complete communities” from scratch, since a “complete community” depends upon a myriad of services. When the first household arrives in an incomplete “edge town” (like Kitts Creek, shown above), they may be able to walk to other houses and some services. New services won’t arrive until there’s sufficient population to support them — and in many cases, rely upon people living even further out. Contrast that with a new house within an existing “complete community,” which already has all of that community’s services at their doorstep, from day one.

I’ll note that mode shift is less statistically significant because, outside of a few urban cores where destinations are so close by that walking is enjoyable and driving a pain, driving accounts for a substantial majority of Americans’ trips. That makes development within those few urban cores that much more important, in the scheme of shifting Americans away from automobility.

Thus, the most effective land use tool that urban planners have to address the global warming crisis — and at minimal public cost, to boot — is to make infill development easier.

Applied on a global scale (or even at a citywide scale), the potential is vast: 2014’s New Climate Economy report estimated that “compact, transit-oriented cities” could keep 1.8 billion tons (CO2 equivalent) of global warming pollution out of the air annually by 2050. That’s equivalent to decarbonizing the entire US transportation sector, or the economies of Russia or India.

Friday photo: The first sprouts in a freshly plowed field will be weeds

Country road again

An ecological analogy for retail:

Many of the plants we call weeds originally evolved in tough conditions, where there is annual glaciation, periodic flooding, or severe fires – extreme events that leave exposed, bare earth. It’s in these devastated conditions that our weeds are at home. They germinate first and grow the fastest. And through these characteristics they have found important roles in re-establishing healthy ecosystems… Once the weeds are established, longer-lived plants, less adapted to disturbance, germinate and the process of succession begins. The process may end in a grasslands, woodlands or forest, depending on the soil and climate. Indeed, the weeds create the conditions of their own inevitable demise – inevitable unless of course the disturbance recurs.

The “weedy species” that so many bemoan, the token dry-cleaners and fast-food joints that sprout in brand-new buildings, are one key to building a retail market. Over time, better adapted shops will take root — and given enough stability, species will evolve into very specific ecological niches. These new species will both adapt to their environment, and also change the environment around them. The key is to give the habitat time to evolve by avoiding excessive disturbance — a condition ecologists call “disclimax.”

Cultivating biodiversity requires striking the right balance between stability and renewal. The goal should be less to conserve individuals than to maintain the health of overall communities, to not seek out stasis forever but to manage change for the long term.

Gradual change within human communities also helps to sustain and build linkages, according to a paper by sociologist Katherine King: “A gradual pace of redevelopment resulting in historical diversity of housing significantly predicts social relations.”

Friday photo: Bonsai, artificial limits to growth, and humility

Phipps: bonsai since 1960

Cities are living things that require supporting infrastructure: physical infrastructure, social infrastructure, green infrastructure. They also need room to grow and change.

The exception that proves the rule are bonsai, “the most unnatural nature that exists,” and “like a verb…. not a noun — it’s doing.” Trees can survive when confined to tiny boxes that constrain their growth. This 55-year-old Scotch Pine at the Phipps Conservatory would, on a managed plantation, have a trunk one foot wide — wider than the magazine at right, about half the diameter of the planter this tree lives in — and be 60-80′ tall.

However, bonsai require a lot of care and feeding just to survive, including extensive pruning to thwart natural growth instincts. Without that pruning, the tree gradually consumes all of the soil’s nutrients and starves. All this intervention turns what should be a robust, independent tree into a fragile hothouse flower, subsisting on life support. At this juncture, even if it was freed from its constraints, this tree could never match the size of its wild counterpart. It’s a neat inversion of the usual relationship between man and nature, but like seeing a bored tiger at a zoo, it’s also a bit sad to see.

Natural systems also impose limits on their own sustainable growth, of course. Cycles see growth culminating in decline and death, then renewal and evolution. But nothing that’s alive stands perfectly still.

Those who propose to stop growth should have the humility to acknowledge that doing so will change the very nature of growing things. By giving themselves free rein to change the city, they are placing a tremendous burden on the resources of future generations.

Will Mayor Bowser recommit to Sustainable DC & MoveDC?

[updated 1 April]

In a recent speech to District Department of Environment employees, Mayor Muriel Bowser offered some warm words about Sustainable DC — but fell short of a full-throated endorsement:

The decisions that we make are often, I would always say, 50 year decisions… The decisions we make around transportation options, whether we put something someplace or not — again, 50 year decisions. What is clear is that we’re making decisions right now that affect the next generation, and shape the options for the generation after that.

We have to be very careful in government about how we distribute our resources, and how we take care of the community. We inherited it, and we have to leave it better for the generations that follow us…

I inherited the past successes… I inherited some good things, and one of those good things was Sustainable DC. And so what I know Tommy [Wells] will do with me is make recommendations on all the things we should keep, all the things we should push harder on, the things we have to add, and if there are things we have to change or delete we should do that too…. I was elected for a fresh start, not a start all over, and so we want to make sure that we’re building on the successes of your hard work… and push the District even farther.

Mayor Gray leaves behind a substantial legacy of ambitious plans, particularly Sustainable DC and national award winning direct descendant Move DC. Both began with citywide public involvement, set ambitious performance goals, and have started to guide real implementation efforts that would, if continued, really advance the long process of creating a truly sustainable District.

Just to put one of those performance goals into a global perspective, Sustainable DC has twin goals of increasing the District’s population by 40% and shifting 75% of commute trips out of cars — baseline goals that MoveDC started with, and crafted an implementation strategy around. Alex Block points out that this is certainly doable, but it isn’t easy.

MoveDC capacity targets

To do so will require more than doubling transit capacity, almost tripling bike capacity, and cutting car capacity by 7%. It would avert over one milion VMT every weekday — which (with current emissions factors, which assume today’s technology) would cut 580 tons a day from DC’s carbon emissions, more than 3X as much as the reviled Capitol Power Plant puts out.

Smart growth policies like MoveDC are a fine example of acting locally while thinking globally, as these are local policies that would have global consequences. The National Research Council & TRB estimate that a national shift towards denser development — including shifting more population growth into the District from the suburbs — would cut CO2 emissions from driving by 11% by 2050, even before any change in vehicle technology. That’s 132 million metric tons of CO2 each year, an amount exceeding all coal emissions from DC, Maryland, Virginia, and West Virginia. Or, put another way, smart growth cuts driving, which could cut as much CO2 as shutting down all of our region’s coal power plants.

Of course, we will absolutely need to do both — and much more — if we’re to have any hope of avoiding a certain existential threat to DC’s future. But only smart growth and energy efficiency cut emissions over the long run, and pay for themselves in the short run.

On definitions: equitable communities, magpie infrastructure, vibrant centers, gentrification

Bellevue goes upscale

Bellevue was not one of the “suburban vibrant centers” examined for a NAIOP report on office occupancy trends.

Some recent reports left me appreciative of their aims and ends, but not exactly how they got there, and in particular with how other analyses have defined key terms.

1. The Living Community Challenge certainly provides an inspiring goal to reach for, notably in its use of elegant performance criteria that broadly require “net positive” environmental performance on site — broadly, that new developments can strive to shrink their ecological footprints to fit within their actual footprints. It also pretty seamlessly integrates the Transect throughout, and in a balanced way that sometimes rewards and sometimes penalizes both ends of the spectrum.

However, having participated in the creation of LEED for Neighborhood Developments, it’s telling that some of the same battles in that scheme have emerged within this one. Prescriptive approaches still occur throughout, and some of the personal-health ones are somewhat wishy-washy. (The emerging science of health impact assessments may have been a useful complement here.) The equity section (“petal”) has a lovely intro, but its imperatives don’t address many social criteria — affordable housing is a notable omission — and almost entirely use prescriptive standards. Another long-running debate was over the use of prerequisites in the rating scheme: It seems strange that a baseline, “Petal Community” certification can be done while ignoring a majority (four of the seven) of the petals.

I’ll be interested to learn more about the Challenge in the coming weeks, and to see how others feel about whether it’s rigorous and balanced.

2. Kriston Capps brings up Mikael Colville-Andersen’s term “magpie infrastructure” in a recent CityLab piece. Bicycle and pedestrian infrastructure, examples like the Bloomingdale Trail aside, rarely needs architects’ attention — their structure-first solutions are usually fundamentally anathema to bicyclists’ lazy inclination to not climb hills. By and large, people should be encouraged to stay at grade, and landscape architects and engineers should be entrusted with their care.

Closer to MCA’s home, the current BIG exhibit at the NBM includes Loop City (video; skip to 2:30), a proposal for an elevated rail loop around Copenhagen + Malmo. The proposal lifts up the stations so that trains decelerate on the approach and accelerate as they exit — a clever idea lifted from subways like Montreal’s. When done below-ground, this brings trains closer to the surface just where they’re needed, but when above-ground, the same approach antagonizes the energy needs of the passengers (who need to climb ever-higher escalators to get to the platforms) and the energy needs of the trains.

Another obvious flaw is that the proposal repeats the Corbu-in-Algiers mistake of thinking people would want to live in flats beneath a railway, without realizing that below-the-tracks spaces are almost always only valuable in situations (I’m thinking in Ginza, the Viaduc des Arts, or 9 de Julio) where such space is just the cheapest way of getting valuable ground-level, street frontage. Even maglevs are pretty awful to stand right underneath.

Besides, haven’t we tried grade-separation of different modes before?

3. NAIOP recently published a report offering slight encouragement to the notion that office users are increasingly choosing mixed use environments — namely, 24-hour CBDs and 18-hour “suburban vibrant centers” (their terminology, not mine) — over single use suburban office parks. Their findings indicate that rental rates are indeed higher in CBDs, but that CBDs haven’t seen as much absorption as suburbs, whereas “vibrant” parts of suburbs had a verifiable edge in the leasing market. There’s certainly plentiful anecdotal evidence, and this has been the mantra of “Emerging Trends” and other qualitative reports for quite some time, but I’ve seen few attempts to quantitatively analyze the phenomenon.

Yet the two sets were compared quite differently. The comparison of CBDs vs. suburbs was strictly quantitative, an approach that didn’t control for the quality of the urban environments — downtown absorption was hurt by including a great many “dead” downtowns (Dayton, St. Louis, Hartford) among the comparison set. Most of the liveliest downtowns have seen strong positive absorption, since it’s less the CBD location than the mixed-use amenities that draw users.

The “vibrant centers,” on the other hand, were compared using a robust paired-case approach: single-use suburban areas were paired with mixed-use suburban areas within the same part of town. They even came up with a pretty strict definition of such centers and their comparison sites, using Walk Score and building-level maps. This better methodology dives into why people are migrating towards such sites, and goes beyond the not-terribly-nuanced submarket definitions found in typical office market reports.

Although the lower absorption figures for CBD office may look discouraging at first glance, it’s necessary to consider both that higher rents might result in tenants using CBD space more economically. Square feet don’t necessarily correspond with people, much less dollars. (Edit 26 Feb: City Observatory has a new report indicating that job growth has indeed been more robust in CBDs than in suburbs.) In addition, the supply constraints on new downtown office might suppress demand from space-hungry users — e.g., many large companies are expanding both in San Francisco and Silicon Valley, but adding more jobs in the Valley where construction isn’t limited by constraints like Prop M.

4. For good measure, here’s one instance where the methodology and the results both turned out okay: Governing’s recent analysis of gentrification at the Census tract level. The scale of the analysis is correct, the results pass the smell test, and the variables used (rankings of changes in household income and physical [home values] and cultural capital [college attainment]) seem reasonable.

A rising Potomac: oh, dam it

30m sea level rise along the Potomac

30 meters of sea level rise would wipe out most of the L’Enfant City, put the White House underwater, and leave the Capitol on a little island — but it could still be managed by damming the Potomac River at key locations, like Quantico or Mason Neck.

Of the world’s major coastal-plain cities, Washington, Rio, and London are among the few that could conceivably be saved by damming estuaries, although I’m sure the Japanese will still try. (Or maybe Houston.)

The same can’t be said for Philadelphia, where the Delaware has a very broad valley, or even New York, where dams at Verrazano Narrows and Arthur Kill will have to be supplemented by very extensive construction to block Long Island Sound. Boston either becomes an archipelago or a polder at a mere 7m of SLR. Even Montreal faces serious property loss over 20m; at 30m Beijing becomes coastal and tides could reach Lake Champlain and the Caspian sea.

Much more than 30m, like the 60m these guys have in mind, and most everything on the east coast below the fall line would be gone. Even dams at the Golden Gate and St. John’s would no longer protect San Francisco or Portland. That’s when inland real estate might become rather more valuable.

Surprisingly, my river-view apartment should be okay up to +10m or so even without a downstream barrier.

Generated using

[Posted to Flickr on 12 June 2012, but today’s Antarctic ice sheet news reminded me that I never cross-posted it here.]