Greater Greater Washington

Past Posts

Breakfast links: Bike lanes coming


Photo by Elvert Barnes on Flickr.
Next bike lanes: DDOT is proposing ten new bike lanes on nine miles of major streets including Pennsylvania Avenue west of the White House. While not protected bikeways, they still require removing lanes of traffic. (TheWashCycle)

More Metro fallout: DC encrypted its fire department radios but never told WMATA, officials say. Metro was trying to troubleshoot when the incident occurred. (Washington Times) ... The death and injuries could mean many lawsuits. (City Paper)

No endangered species: After 10 to 15 searches in Rock Creek Park within Montgomery County, an American University professor has found no evidence of any endangered crustaceans near the proposed Purple Line route. (Post)

A vision, realized: Ten years ago, DC's former planning director Andy Altman planned a new neighborhood around the Navy Yard. Now, he's back and is amazed at the transformation that he envisioned long ago. (City Paper)

Candidate campaigns on Metro: State delegate Scott Surovell is running for state senate and listed extending the Yellow Line as a top priority. (Fairfax Times)

The wandering museum: The National Children's Museum tried to get a spot on the Mall, then at L'Enfant Plaza, but the recession scuttled plans. So it moved to National Harbor, but couldn't attract enough donations for a building. What's next? (Post)

We're driving less: The number of miles that Americans travel by car each year is falling since a peak in 2004, with many states peaking in the 1990s. Researchers think that car travel and economic activity are no longer coupled together. (Post)

And...: New bike grip technology claims to provide "eyes-free navigation." (CityLab) ... How should cities handle the demise of the parking meter? (Bacon's Rebellion) ... When is it appropriate for bicyclists to pass cars at a stoplight? (City Paper)

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Here are the answers to whichWMATA week 35

On Tuesday, we posted our thirty-fifth photo challenge to see how well you know Metro. I took five photos in the Metro system. Here are the answers. How well did you do?

We got 41 guesses this week. An amazing 12 of you got all five. Great work, Alex B, Peter K, dan reed!, Mr. Johnson, K Conaway, Spork!, MZEBE, DAR, Justin...., hftf, Chris H, and Frank IBC!


Image 1: Wiehle Avenue

I snapped the first image on the Wiehle Avenue station's southern bridge. The main clue here is the freeway below. You can see the six eastbound lanes of the Dulles Toll Road and Dulles Airport Access Road. The gambrel roof of the station, which is visible at left, also narrows this down to one of the three new Silver Line stations with that roof type. Thirty-two of you knew this one.


Image 2: Fort Totten

The next image shows the bus loop and upper level platforms at Fort Totten. One clue here is the tall steel beam running along the station. This is part of the bridge structure that holds up the CSX tracks that flank the Metro tracks between Brookland and Silver Spring. Takoma and Silver Spring also have similar beams, but their layouts are different. The bus loop, which extends under the bridge, is the clearest indicator that this is Fort Totten and not Takoma. Another clue that this isn't Takoma is that the platform continues above the roadway, which is not the case there. Thirty-two guessed correctly.


Image 3: Eisenhower Avenue

The third image was taken from Eisenhower Avenue looking north. At center is an inbound Yellow Line train. The tracks that split off here turn west and go into the Alexandria Rail Yard, which is along the Blue Line. These lead tracks allow Yellow Line trains to be put into service without first going to King Street and reversing. The perspective (off to one side of the tracks) also means that this is a side platform station, which considerably narrows the field. Twenty-eight of you got this one.


Image 4: Wheaton

This picture shows the pedestrian bridge over Viers Mill Road that links Wheaton station to its parking garage and the Wheaton Plaza shopping mall. It's a fairly distinctive bridge, and there aren't any others in the Metro system that share its design. Twenty-seven knew this was Wheaton.


Image 5: Foggy Bottom

The final image shows the entrance to Foggy Bottom station. Metro completely rebuilt this entrance a few years ago. Prior to its reconstruction, it had three escalators. But when one or more was broken, the lines to get into and out of the station were legendary. When WMATA rebuilt it, they put in three new escalators in such a way that there was room for a staircase. The LED lights glinting off the sides of the escalator are a clue here. Another clue is the building visible just outside, which is on the northeast corner of 23rd and I NW. Twenty-two got this one right.

Thanks to everyone for playing! Great work. Stay tuned. We'll have five more images for you next Tuesday.

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We're doing great stuff! Want to help?

As we move forward with our 2015 goals, like holding a speaker series, doing live chats, hosting how-to-blog workshops, relaunching the site, and kicking our social media into higher gear, we need more hands.


Image from Wikipedia Commons.

Becoming a contributor is a great and important way that you can get involved in Greater Greater Washington any time, but if you'd like to help in other ways, right now we could really use assistance with several non-writing elements.

All of the volunteer roles below are ongoing, with a commitment of a few hours per week, every week (except where noted).

Social media: We're on Twitter and Facebook, but for a long time, nobody on our current team has been able to focus on packaging and sharing our posts on those platforms, and it's an area that with a little attention, could really become great.

Do you have a flair for social media? Are you willing to take on these accounts? You would monitor them, help our editors and contributors improve their tweets and headlines, and collect some statistics on how we're doing so we can see where we acn improve.

Events: Our community happy hours and the panel discussions we're hoping to start on urbanist issues are fascinating and fun, but they do require some work to plan, like securing venues, picking dates, coordinating with speakers, and handling logistical details. If this sounds like your talent, we'd love your help!

Live chats: During last last year's DC mayoral candidate live chats, we learned one of the most critical components to make it successful: fleet fingers! Our chats require at least 3 incredibly fast (70-90 wpm), accurate typists taking 2-4 hours out of the middle of their day to go to the chat location, prep with their fellow typists and moderator, and then type like their fingers are on fire for an entire hour.

But the good part is, if you'd like to get involved but can't commit to a weekly task, we can add your name to a file and give you a call when we're planning a chat.

Expanding our coverage: This one is about writing for us. We're lucky to have amazing contributors covering a range of issues, but there are issues we'd like to discuss even more

Natalie Wexler and sometimes Dan Reed write about education issues for us in DC and Montgomery County, and our education posts have great readership, but we'd like to do even more coverage of how education impacts the shapes of our cities and neighborhoods.

We'd also like to talk more about affordable housing policies and the experiences people have who live in or need to find affordable units. We talk a lot about the ins and outs of transit or bicycle design, but the economics and stories around housing are also extremely important.

And we'd like more articles about neighborhoods east of the Anacostia and in Prince George's County as well as in Fairfax and farther-out parts of Virginia. If you live in these communities, what debates are people near you having about the future growth of your area? What do you want to see change? We'd like to share this with our readers.

Consider this our open call to you, and if you're interested in any of the items above, email us at info@ggwash.org with the subject line, "HELP GGW: [what you want to help with]." If you have questions, post them in the comments, and we the editors will do our best to answer them!

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BREAKING: Hogan gives the Purple and Baltimore Red lines a momentary reprieve

New Maryland governor Larry Hogan will include some funding for the Purple Line and Baltimore's Red Line in the state's budget, though the fate of both projects remains unclear.

Both the $2.4 billion Purple Line, a proposed light rail line between Bethesda in Montgomery County and New Carrollton in Prince George's County, and the $2.6 billion Red Line light rail, which would connect Woodlawn in Baltimore County and Bayview in Baltimore City, are ready to start construction this year.

The state would only have to provide a small portion of the total cost, roughly between $300 and $700 million for each line. Each project already has funding commitments from local jurisdictions and the federal government, while the Purple Line would also receive funding from a public-private partnership.

Until the formal budget release tomorrow, we won't know how much funding Hogan has set aside for either project. He could provide enough money for each project to move ahead as they are, or request additional study or cost-cutting. That could imperil the federal government's $1.8 billion commitment for both projects, which would be distributed to other projects in other states if Maryland doesn't take the money, as well as the private funding.

Hogan, a Republican who beat Democrat and former lieutenant governor Anthony Brown in an upset election last fall, vowed in his campaign to reduce government spending to close the state's budget shortfall. While he said he would not make a decision on either the Purple or Red lines before taking office, he previously expressed a preference for building roads over transit and focusing on the state's rural areas.

Also included in the governor's budget is $30 million for a new regional medical center in Prince George's County, at Largo Town Center Metro. Hogan also proposed cutting in half a formula that provides additional funding to school systems with a high cost of education, called GCEI, which would specifically affect Montgomery and Prince George's counties.

We'll provide more details as they come.

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The Air and Space Museum needs a new skin

In the four decades after it opened, the National Air and Space Museum has become one of Washington's most well-loved attractions. Its building hasn't aged so well.

The window walls are outdated, skylights leak, the mechanical systems are dying, and the terraces are leaking into the basement car storage. But much worse than that, the stones that clad the building are bowing and cracking, which threaten to make it uninhabitable.


Photo by Terry (α) on Flickr.

Usually, there's nothing wrong with getting wrinkly at 40, but here, the 12,000 stone panels are pretty much the only thing keeping water out of the building. When they deform, they expose the building to more and bigger leaks. They could also break and fall onto someone.

We think of stone as unfailingly solid. But, like in most buildings built after 1900, the stones at the Air and Space Museum form a veneer that carries no weight. This approach has worked quite well in most cases, but if the stones are too thin, or installed the wrong way, they can deteriorate.

When thin stones fail

The museum's stones are 5 feet long, 2½ feet high, but only 1¼ inches thick. Beginning in the 1950s, engineers and architects tried to apply stone as thinly as possible to make buildings more cost-efficient.

Things went well for denser stones like granite and on buildings in warmer climates. But beginning in the 1970s, spectacular failures started to occur when soft marble covered a building in a cold climate, like Finlandia Hall in Helsinki or the Standard Oil Building in Chicago.

The stones started bowing due to a phenomenon called "thermal hysteresis."

Imagine a slab of stone sitting in the sun. One side gets warm from the sunshine, while the other does not. The sunny side expands and contracts differently from the other. If the stone is too thin, the flexing can damage the crystalline structure.


The warping is visible when the sun hits the panels at a low angle. Image from Google Maps.

Stone comes to the National Mall

The Air and Space Museum is clad in a stone called "Tennessee pink marble," although it's technically not marble, but a particularly crystallized form of limestone.

John Russell Pope introduced the stone to the National Mall with his 1941 National Gallery of Art. The warm color and faintly glittering texture was a welcome alternative to icy marble, dull limestone, and harsh granite. Because the National Air and Space Museum was across from the National Gallery, the Commission of Fine Arts pushed its architect, Gyo Obata, to match it.


The south side elevation shows more damage where the tiles are more exposed to sun.

But Pope used stones four to eight inches thick and installed them in a heavy and redundant way. IM Pei's stonework on the 1978 East Wing also had serious problems, but those stones were 3 inches thick and the problems primarily came from the way the stones hung on the building, which the Gallery was able to fix.

That will not be possible at the Air and Space Museum.


Section drawing of how the stones sit on the steel frame.

Too thin is just the beginning

The panels are pinned together end to end through holes drilled through the stone. As the panels warp at different rates, stainless steel rods apply enormous pressure to an extremely thin layer of stone. The brittle stone is liable to crack and even shed pieces.

The stones also sit on metal rails connected directly to the steel frame, so unlike with the National Gallery buildings, they're subject to the frame's motion. Already by the 1980s the Smithsonian had to widen the joints between the stones to reduce damage.

As the stone cracks, an inner cavity opens to the elements. Normal buildings have a membrane or second wall to prevent moisture from moving through the outer walls. Here, the only protection is foam insulation sprayed onto the inner face of the stone.

Finally, between the stones and walls of the exhibition halls is a large open space that carries used air back to the ventilation system. This means that the thin stones are the only thing between inside and outside. Ironically, reconstruction architect Larry Barr remarked that the constant airflow was probably the only reason there wasn't severe water damage or a mold problem. Moisture could simply never accumulate with the continuous flow of dryer air.

Some solutions are obvious, others require tough choices

The building needs a new facade, new windows, new equipment, and repairs to the terraces. You shouldn't have to renovate a building, let alone a monumental one so soon, but the renovation offers the opportunity to correct 40-year-old mistakes and build for at least another hundred.

In the 1970s, inflation encouraged cost-cutting and buildings were adding elaborate mechanical systems long before their performance was understood. Sustainability was not yet a concern for architects. The museum, which had stalled for two decades, was then rushed to be ready for the 1976 United States Bicentennial and opened days before the 4th of July.


Earlier design for the museum. Image from the Commission of Fine Arts / HOK.

But building technology has improved a lot, so there is a silver lining. Fixing a relatively typical problem like the terrace waterproofing affords the opportunity to replace it with more proven systems, brush up the planting, and improve circulation around the site.

Much better glass technology including durable films to block unwanted radiation, newer seals, and better insulation would make for a better experience on cold days and muggy afternoons. The design team is even considering installing solar panels onto the roof, reducing carbon footprint and partially shading some of the skylights.

Other projects, such as redesigning the entrance for security purposes, offers the opportunity to make the building's entrance more engaging. A similar level of attention could be paid to the Independence Avenue side of the museum, which stands out as particularly pedestrian-unfriendly.

The big decision is how to replace the stone and its supporting system. The museum asked Quinn Evans Architects to prepare for a reconstruction of the exterior, in four options: thicker Tennessee stone, sturdier pink granite, a ceramic system, or titanium. The latter two would bring new materials to the Mall and disrupt the match between this and the National Gallery, but would be more resilient and arguably interpret the building's content better than stone.


Four possible options for replacing the stone.

The four options are deceptive, because of the wide range of textures possible with each material. Titanium can come in flat, smooth panels, or it can be scalier, like the titanium used on the Guggenheim Bilbao. Ceramic systems, too, can take a wide range of textures and forms. The options go beyond just copying the 2.5' by 5' stones as the rendering above suggests.

In any event, it makes little sense to fret over preserving the architecture. It is not a universally loved building. In a chat about America's landmarks, Stanley Tigerman characterized it as "not even architecturally interesting," pointing out that the building's content occupies a more prominent role in the memory of Americans than the architecture itself

Perhaps a little bit more ambition and thought can mean we needn't repeat this renovation in 2055.

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A green wave gives cyclists a stop-free trip

One tool that planners have to calm neighborhood streets and encourage bicycling is a "green wave." Engineers set the traffic signals so they turn green just as a vehicle traveling at a certain speed arrives.


Sign on Valencia. Photo by the author.

The basic premise of the green wave is to control the average speed on a segment of road. For example, if speeding is a problem in a corridor, the signals can be set for, say, 20 miles per hour. If drivers speed, they'll only end up having to wait.

But green waves can also be set to benefit cyclists. That's the case on Valencia Street in San Francisco, where the signals are set for 13 miles per hour, a very comfortable speed for most cyclists.

I had the opportunity to ride Valencia last summer when I was in San Francisco, and it was an almost religious experience.

The street has bike lanes, which give cyclists their own space, and saves them from feeling pressure to ride faster that motorists can sometimes bring. But riding along at a comfortable 13 mph, the signals turn green just as the leading edge of the wave gets there.

This happens again and again at every intersection. I felt like the hand of God was turning the signals green for me. That's how amazing it is.

There may be streets in DC where this approach could work easily. I used to ride 11th Street from Columbia Heights into Downtown frequently. And on that street, the seemingly random nature of the signal timing meant frequent stops and starts, for both cyclists and motorists.

Of course, green waves are easier said than done. In a complex gridded city, perpendicular streets also have signal timing that needs to fit into a larger pattern. But in targeted corridors, a green wave can calm traffic and encourage cycling.

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Breakfast links: Tunnel and surface


Photo by Kevin Harber on Flickr.
Anomalies in our tunnels: NTSB investigators found "anomalies" with the ventilation fans in the Metro tunnel that filled with smoke last week. Metro will change its protocols and add signs to tell first responders how to open the trains. (NBC4)

Better buses in Tysons: Fairfax Connector will rearrange some bus routes in Tysons Corner to make them more direct. (The Tysons Corner)

VDOT likes toll lanes: VDOT wants to add toll lanes on I-66 both inside and outside the Beltway. It would widen I-66 outside, and inside, charge rush hour tolls for non-HOV vehicles. Will it also add bus service? (WTOP)

It'll stay short: DC historic preservation officials oppose any efforts to add floors to the MLK Library except for a single, smaller, set back floor on the top. The preservation board will only consider two of these more restrained additions. (City Paper)

Powerless merger: Plans for Pepco to merge with Chicago-based Exelon might be bad for the area. While Exelon is a much larger company that could provide more power reliability, its interests may not align with the region's. (DCist)

New versus old: A mixed-use building like thsoe going up in Logan Circle could transform Congress Heights. But it will replace four older buildings whose tenants aren't keen on leaving and say the landlord has mistreated them. (City Paper)

What's the answer?: Why is there no F Street SE in most of Capitol Hill? Why do walk lights get turned around? Why do the Capitol Police search buses? What's with the funny street names? The City Paper answers these questions and more. (City Paper)

Where it is: These ten maps about DC show where are the best transit, the most trees, the rats, the food deserts, and much more. (Post)

How will we change?: The Urban Institute's new "Mapping America's Futures" tool lets you explore different scenarios for how metropolitan areas will grow and shrink in population depending on the birth, death, and migration rates.

Slow train to LaGuardia: Governor Cuomo's proposed rail link to LaGuardia actually would take longer than current buses for almost everyone. Actually, any likely alignment would also be slower than buses. (The Transport Politic)

And...: The DC Council will hold a hearing on the L'Enfant Metro incident. (WAMU) ... The man who shot two people on an X2 bus has been arrested. (WMATA) ... Montgomery County may follow Fairfax County and push school start times later. (NBC4)

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Awaiting a decision, activists rally for the Purple Line

Maryland's new governor, Larry Hogan (R), is expected to announce his budget on Friday. Among its many facets will be funding, or a lack of funding, for the Purple Line. Advocates are mobilizing on social media to ask Hogan to keep the project moving forward.


Images from Purple Line Now.

Since winning office, Hogan has remained mum on the line, which will run from Bethesda to New Carrollton, as well as the Baltimore Red Line. During the campaign, he said he thought both were too expensive, but once elected, he said he would evaluate the projects carefully.

Business groups have organized to support the line, which they say is key to Maryland's economic competitiveness. It already has federal money attached, which could help bolster the case, though that hasn't stopped other governors (like New Jersey's Chris Christie) from canceling transit projects.

Supporters have changed their Facebook and Twitter profile photos and tweeted with the hashtag #purpleline. Some even co-opted Hogan's slogan, "Change Maryland," suggesting that the Purple Line represents positive change for Maryland.

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Ask GGW: Is there any reason not to have a sidewalk?

There are parts of DC and other cities with no sidewalks. As pedestrian safety has become a higher priority in road design, DC and other cities have been adding them, though sometimes residents oppose the idea. Is there any good reason not to put one in? Do we have statistics?

Reader Phil L. asks: "Do sidewalks measurably improve pedestrian safety even in low traffic density areas, like residential neighborhoods? What would be a compelling reason to have a residential street without a sidewalk?"


Photo by thisisbossi on Flickr.

Erin McAuliff says:

According to the National Complete Streets Coalition, "Pedestrian crashes are more than twice as likely to occur in places without sidewalks; streets with sidewalks on both sides have the fewest crashes." I think the reference for this is from the Federal Highway Administration.

From another angle, and with a particular focus on the aging, sidewalks may increase residents' perception of safety. Falling or tripping on poorly maintained sidewalks is a serious concern for the elderly, especially the frail, for whom one accident could be devastating. Falls are the leading cause of death from injuries for persons over the age of 65.

Ben Ross gives some historical perspective on why neighborhoods might not have them:
The original reason for not building sidewalks in suburban neighborhoods was to give the development a "high-class" non-urban image by discouraging walking. See Dead End, page 16.
Sean Emerson lives in one such area:
A reason I've heard people in my neighborhood (Woodmoor in Four Corners) use for opposing sidewalks was the preservation of the "rural" feel of the neighborhood. My neighborhood and several others nearby were once anchored by Indian Springs Country Club, so you can imagine that the clientele originally buying homes around here were doing so to escape the city and its associated "urban" infrastructure like curbs and sidewalks.

The streets in my neighborhood close to University Boulevard and Colesville Road were built in the mid-1930's with no sidewalks or curbs (these streets comprised the original development anchored by the country club). When the county installed curbs about 10 years ago, sone people complained that the curbs changed the "character" of those streets, and several think that sidewalks would make it worse. There are many 1930's era neighborhoods in and around Silver Spring which still lack curbs of any kind, much less sidewalks (Hillandale, North Hills of Sligo, and parts of Woodside come to mind).

Retaining a "country" or "rural" feel might not sound like a compelling reason to prevent the installation of sidewalks to most, but it is for some.

So does Nick Keenan:
My neighborhood, Palisades, had a protracted debate about adding sidewalks on a neighborhood street, University Terrace. Ultimately they were not put in.

Some of the arguments were expected: there are people who never walk, who don't see any utility to sidewalks. Landowners who would lose part of their front yard were predictably opposed. What surprised me was how many people expressed the viewpoint that sidewalks actually detract from a neighborhood. People even used the adjective "rural" to describe our neighborhood. I'm not sure they really knew what rural meantPalisades certainly isn't rural I think they were looking for a word that meant non-urban and that was the best they could come up with.

Like so many personal preferences, there's no right or wrong, but there's also very little room for persuasion.

Not all neighborhoods of that era lack sidewalks. David Rotenstein writes:
It's a mistake to generalize that all 20th century residential subdivisions omitted sidewalks or that the failure to install them was part of some larger, mysterious anti-pedestrian agenda. One Silver Spring subdivision (outside the Beltway) originally was developed between 1936 and 1940 and the subdividers/developers intentionally constructed sidewalks and used their existence as a marketing point in sales literature.
Coming back to the issue of statistics, Jonathan Krall writes:
The "safety in numbers" effect, often discussed in relation to cycling, also applies to pedestrians. Briefly, injuries per pedestrian fall as the number of pedestrians increase. This implies that adding sidewalks to an area would encourage walking and make that area safer.

However, it is difficult to square that result with the nationwide increases in pedestrian fatalities, happening during a decrease in driving and (I presume; I don't have data on this) an increase in walking

My hypothesis is that the shift towards transit (and presumably walking) that is so clear in data for millennials is leading to more walking in suburban environments along dangerous arterial roads. But that is just a hypothesis.

But Ben Ross challenges the premise that statistics can explain the sidewalk debates:
"Safety" is not the main issue here. It's equal treatment. Lack of sidewalk discourages walking by denying pedestrians the right of way. They must get out of way whenever a car comes by.
David Edmondson explains how just slowing cars down can improve safety:
It's likely not simply an issue of traffic volume but of traffic speed. Take, say, this random street in California. It's narrow but two-way and so traffic is very, very slow (roughly jogging speed). Despite its lack of sidewalks, it is a pedestrian-friendly streetI see unaccompanied kids on such streets all the time. Yet I would not feel comfortable walking down other sidewalk-free streets (like this one in Silver Spring) where calm traffic is not invited by the street's design.

I don't know of any studies regarding sidewalks and pedestrian safety on low-volume streets, but I don't think that's the right way to look at it anyway given all the factors that go into a street's safety. Risk is a quality positively correlated with increased volume and speed and sight-lines, each of which are themselves correlated with certain street design choices. A pedestrian is shielded from some of that risk by a sidewalk, but sometimes the risk is so low that the shielding is unnecessary.

Do you have a question? Each week, we'll post a question to the Greater Greater Washington contributors and post appropriate parts of the discussion. You can suggest questions by emailing ask@ggwash.org. Questions about factual topics are most likely to be chosen. Thanks!

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Harriet Tregoning opposes DC's row house downzoning plan

Mere months after she stepped down as head of DC's Office of Planning, Harriet Tregoning's former agency came out with a proposal to limit the height and numbers of units that can go in many row houses. Tregoning has now sent a letter to the DC Zoning Commission opposing this plan.


Photo by Thomas Le Ngo on Flickr.

She writes,

I am afraid conclusions about development pipeline outcomes and impacts on single family housing costs (and subsequent recommendations for down zoning and other zoning changes) are being drawn from too narrow and recent a time period. Yet the consequences of Zoning Commission action may affect the city for decades to come.
In other words, OP is hastily acting based on limited data, but could hamstring the city for a long time.

Tregoning headed OP from 2007 to 2014, when she left for a position in the federal Department of Housing and Urban Development. She wrote the letter entirely in her personal capacity as a resident of Columbia Heights, a neighborhood largely in the zoning category (R-4) that this proposal would affect.

The change came out of public concern about "pop-up" additions to row houses. OP suggests limiting the height in R-4 row house zones to 35 feet, which is still enough to build a third story. That means that it won't stop all pop-ups.

As Tregoning points out, the real public hatred comes from ugly pop-ups (which people can still build under OP's plan). She writes,

There have indeed been some awful additions built in R-4 and R-5 neighborhoods. However, I don't believe that the builders of the additions aspire to horrify the neighbors and potentially devalue their own property; I think they are terribly uninformed about what makes for a compatible addition. ... Much of the outcry about "pop-ups" has been over compatibility. However, many additions to rowhouses are so compatible that they are utterly unremarkable in terms of changes to the neighborhood.
Tregoning suggests "an advisory ANC panel of citizen architects or designers to advise builders" on how to make an addition attractive and compatible. It could start out voluntary but become less so if necessary.

Will more restrictions make housing more affordable for families?

The Office of Planning also wants to restrict row houses in these zones to two units. The staff say that this will keep prices down, because developers hoping to subdivide them can't outbid families, and also ensure there is larger, family-sized housing. Tregoning argues this is false, or at least, unsupported by data at this time.

I am somewhat puzzled by the proposition that we can increase affordability by decreasing the supply of potential housing units ...The compet1tion for [rowhouse] housing will be fierce, whether a buyer plans to live there herself, renovate the building as a single family unit for sale, or renovate it as two or more units for sale. Restricting the number of units just limits the housing supply in some of the most central and transit-and amenity-supplied neighborhoods of the city.
Tregoning notes that DC still has more single-family housing stock than families:
I am rather dismayed by the talk of family-sized housing needing to be in single-family dwellings. All over the world families live in what we call multi-family housing (an ironic term given the representation that these units must not be for families)apartments and condominiums.

In DC we are enjoying a mini-baby boom, a product in part perhaps of the influx of young college graduates over the past 7 years and the incentive of free all-day daycare afforded by DC's universal pre-kindergarten for 3- and 4- year olds. But that just means that the City projects that we will have 23% of households with school-aged children in 2030 or so, up from our current level of around 21%. In other words, more than three-quarters of DC households will NOT have school-aged children at home.

Yet roughly 1/3 of the housing supply is of the larger, often single fam1ly or semi-detached housing variety. We do have a mismatchour current housing stock is sized too large for our householdsthat is why so much housing being built and anticipated in the development pipeline are for small units.

Let's not overreact to that pipeline. Recall that we were a shrinking city until roughly 2007, and then we were in a recession. This flurry of building is an attempt to be responsive to demand for smaller units.

Today, almost 44% of all DC households are single-person households. As we attain a closer match between the household size and our building stock, I am confident we will see a broader range of unit sizes be produced.

We already devote more than 54% of the total res1dent1ally zoned land to low density smgle-family detached and semi-detached housing in the R-1 thru R-3 zones. As we see the inevitable generational turnover of that housing stock, more of 1t wlll be avallable for households that want larger housing, including households with children.
However, if we act to restnct housing in the R-4 now, do we really think we can easily reverse that decision once the mismatch of households and building stock has come closer to equilibrium?

Tregoning also says that downzoning all R-4 neighborhoods is unfair to homeowners who purchased their properties with the expectation that they could add on and/or rent out parts of the home in ways that would become illegal. And she says that even San Francisco, a city with a perhaps even more acute housing crunch and a reputation for opposition to new housing, isn't contemplating downzoning residential land.

She argues, as I did, that this proposal should come amid a larger plan for meeting housing demand instead of as a standalone idea. Such a plan might suggest more restrictions on R-4 houses and more new housing in other land types, or a totally different approach.

At some point [the proposed] restrictions may even be appropriate but I do not believe we know that now. What we do know now is that the demand for housing is outpacing supply and that prices are rising such that affordability is threatened not just for moderate income households but for middle income ones as well.
OP needs to create a broader strategy around housing supply and demand so residents can wrestle with the large-scale tradeoffs. Until that can happen, this knee-jerk plan to downzone some row houses is unwise.

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