Tag Archives: Height Limit

Building Height and Density in Center City Philadelphia

With a hat tip to this tweet from John Ricco, linking to this compendium of tall buildings in Center City Philadelphia from the Philadelphia City Planning Commission. The document provides a brief profile of each building, showing building height, site size, gross floor area, floor area ratio, year of completion, and floor count.

Example of information from the Philadelphia FAR catalog. Screenshot from the document.

Pulling the data into a spreadsheet allows for some quick charts to show the relationship between building height and density.

It’s generally true that taller buildings are more dense, but not universally so. Buildings with the same density come in different shapes. Both the Liberty Place complex and the 230 South Broad St have an FAR of ~19.5; but Liberty Place includes a 960′ and 783′ tall towers. 230 South Broad St is just 250′ tall, but the building’s floorplates occupy 100% of the site.

By comparison, the densest zoning in DC is for 12 FAR (the C-5 zone), located in one of the few exception areas for DC’s height limit (allowing 160′ tall buildings along some blocks of Pennsylvania Ave NW). Quite a few blocks are zoned for up to 10 FAR, but nothing in DC can be built to an FAR of 15, 20 or 25, as in Philadelphia.

Considering DC’s effective downtown height limit of 110′ to 130′ combined with a maximum FAR of 10, it’s not hard to understand why DC has so many boxy buildings forced to occupy entire parcels. Likewise, DC’s height limit is indeed a hard limit on office density. Beyond 10 FAR, any additional density requires more height than the law currently allows.

In New York, the Empire State Building has a FAR of about 28. At less than half the height, the Equitable Building (inspiration for New York’s 1916 zoning code) has a FAR of 30.

Note: almost all of these very dense buildings are offices.

Back in Philadelphia, a more obvious example: the obvious relationship between building height and floor count (taller buildings have more floors).

Looking at building height by decade, you can see the clear trend of taller buildings emerging following the end of Philadelphia’s ‘gentleman’s agreement’ on building height – that no building should be taller than the Statue of William Penn atop the City Hall clocktower. This agreement left plenty of room for tall buildings; at 548 feet tall, City Hall was the tallest building in the world between 1901-1908. The agreement was breached by the construction of 1 Liberty Place in 1987.

This particular data set doesn’t include any buildings shorter than the City Hall tower; it’s not a complete record of all construction in Center City, just high rise buildings (the document was published in 2010). You can clearly see the approximate 500′ limit prior to 1987.

If you put all of these characteristics into one chart, you get something like this:

The size of the circles indicate the gross floor area of the project.

A machine to make the land pay

Cass Gilbert’s Woolworth Building. CC image from Wiki.

Cass Gilbert famously defined a skyscraper as “a machine that makes the land pay,” the kind of structure justified (and often required) by high land values. Gilbert’s distillation of the logic behind these buildings is inherently economic (hat tip to Kazys Varnelis):

Speaking of such enterprises from the financial aspect it is a rule that holds almost invariably that where the building costs less than the land, if properly managed, it is a success and where its costs more than the land it is usually a failure. The land value is established by its location and desirability from a renter’s standpoint hence high rentals make high land values and conversely. The building is merely the machine that makes the land pay. The more economical the machine both in construction and operation provided it fulfills the needs the more profitable the land. At the same time one must not lose sight of the fact that the machine is none the less a useful one because it has a measure of beauty and that architectural beauty judged even from the economic standpoint has an income bearing value.

The economic logic still holds. For private development, you need a building that can make the land pay. The challenge, however, is when such a building isn’t feasible – or isn’t allowed. Consider the dilemma of high land prices, high construction costs, and zoning that constrains the allowable building space. Payton Chung raises this issue, investigating why DC doesn’t see more affordable mid-rise construction:

The Height Act limit for construction in outlying parts of Washington, DC, enacted back in 1899, is 90′ — effectively 7-8 stories. This particular height poses a particularly vexing cost conundrum for developers seeking to build workforce housing in DC’s neighborhoods, since it’s just beyond one of the key cost thresholds in development: that between buildings supported with light frames vs. heavy frames…

In most other cities, the obvious solution is to go ever higher. Once a building crosses into high-rise construction, the sky’s ostensibly the limit. In theory, density can be increased until the additional space brings in enough revenue to more than offset the higher costs. As Linsey Isaacs writes in Multifamily Executive: ”Let’s say you have a property on an urban infill site that costs $100 per square foot of land. Wood may cost 10 percent less than its counterpart materials, but by doing a high-rise on the site, you get double the density and the land cost is cut in half.”

In other words, the cost of building taller is not linear. Once you enter the realm of Type I construction, the marginal cost of an additional floor is relatively low. However, Type I construction is substantially more expensive in DC than the mid-rise methods; and many of the 7-9 story buildings ubiqitous in DC fall into the range that require more expensive construction methods, yet do not allow for the kind of height/density those structures can achieve.

The challenge, Payton notes, is where land is pricey enough to justify high-rise densities, but rents in that area cannot support the construction cost. It’s DC’s version of ‘the viability trap.‘

There are a few options to break the logjam: lowering construction costs, and adjusting policies. Payton makes the case for new building technology to lower construction costs – prefabrication, new materails, and so on. Each holds the promise of decreasing construction costs. In the policy realm, reducing the required parking can also substantially reduce costs, providing a pathway out of the viability trap.

For real-world examples, consider Metro’s recent request for development proposals for station-adjacent land the agency owns. Metro’s requirement that the developer replace 422 parking spaces at Fort Totten (in addition to parking required by zoning and/or demanded by the market) likely pushed any development proposal beyond feasibility. That parcel didn’t get any bids. In practice, this isn’t any different from a large minimum parking requirement via the zoning code.

Another policy change is increasing the allowed height and density. In DC’s consideration of altering the city’s height limit, the benefits of scale with taller construction become apparent:

Per square foot construction costs for new office and apartment buildings at 130, 160, 200 and 250 feet peak at 200 feet but begin to decrease at 250 feet due to cost efficiencies that occur at taller heights. Beyond the cost of construction, other conditions need to be in place to make it financially attractive for a developer or property owner to be willing to tear down an existing building with tenants and build new and taller. These conditions include a substantial increase in rentable space due to taller height; the potential for higher rents; major leases expiring or the opportunity to attract a new anchor tenant; or the need for major investment into an obsolete building. There are also a number of constraints that affect new construction, such as the need to pre-lease a major portion of a new building to obtain financing and the inadequacies of existing transportation and utility infrastructure.

A few feet of height can make a big difference.

The zoning straightjacket

The more things change, the more they remain the same.

DC is nearing the end of a lengthy process to re-write the city’s zoning code. The re-write is mostly a reorganization, combining overlays and base zones in an effort to rationalize a text that’s been edited constantly over the better part of half a century. While there are a number of substantive policy changes (all good and worth supporting – reducing parking requirements, allowing accessory dwelling units, allowing corner stores, etc.), the intent of the re-write is to look at the structure and policy of the code, rather than look for areas of the city where the zoning classification should change.

Actual re-zoning will require an update to the city’s comprehensive plan (as all zoning changes must be consistent with the comprehensive plan). As promising as the policy changes in the zoning re-write may be, they do not represent any kind of change to the basic city layout – areas currently planned for high density will see more development, and areas zoned for single-family homes will not.

Last year, the District Government and the National Capital Planning Commission worked on dueling reports (see the documents from DC and NCPC) at the request of Congress on the potential for changing DC’s federally-imposed height limit. Leaving aside the specific merits and drawbacks of this law, the planning team needed first to identify areas that would likely see taller buildings if the height limit were to change.

I’ve borrowed the title of this post from Charlie Gardner, to try to show how little room we’ve planned in our cities for change. Even with the perception of runaway development in growing cities, the amount of space that’s set aside for a physical transformation is remarkably small. Zoning is a relatively new force shaping our cities – about a century old. We’re now seeing the effects of this constraint.

Consider the following examples of freezing city form in place via zoning codes:

Old Urbanist – The zoning straightjacket, part II, writing about Stamford, Connecticut:

In general, the zoning maps continue to reflect the land use patterns and planning dogma of the 1920s, with a small, constrained downtown business district hemmed in by single-use residential districts through which snake narrow commercial corridors.

This, if nothing else, seems like a fundamental, if not the only, purpose and challenge of city planning: accommodating population growth in a way that takes into account long-term development prospects and the political difficulty of upzoning low-density SFD areas. In light of this, can a zoning code like Stamford’s, with a stated purpose of preserving existing neighborhoods in their 1960s form, and resistant to all but changes in the downtown area, really be called a “planning” document at all? The challenges that Stamford faces are not unique, but typical, and progress on them, as zoning approaches its 100th birthday, remains the exception rather than the rule.

Better Institutions – Look at the Amount of Space in Seattle Dedicated to Single-Family Housing, writing about Seattle:

Putting aside the issue of micro-housing and apodments, [ed – I wrote about Seattle’s apodments here] what I’d actually like you to draw your attention to is everything that’s not colored or shaded — all the grey on that map. [ed – here is a link to the map] That’s Single-Family Seattle. That’s the part of the city where most people own their homes, and where residents could actually financially benefit from the property value-increasing development necessary to keep Seattle affordable. It’s also the part of the city that’s off-limits to essentially any new residential construction because preserving single-family “character” is so important. And it’s why residents in the remaining 20% of the city can barely afford their rents.

Dan Keshet – Zoning: the Central Problem, in Austin, Texas:

Zoning touches on most issues Austin faces. But with these maps in mind, I think we can get more specific: one of the major zoning problems Austin faces is the sea of low-density single-family housing surrounding Austin’s islands of high residential density.

Daniel Hertz – Zoning: It’s Just Insane, in Chicago, Illinois:

So one thing that happens when I bring up the fact that Chicago, like pretty much all American cities, criminalizes dense development to the detriment of all sorts of people (I’m great at parties!) is that whoever I’m talking to expresses their incredulity by referencing the incredible numbers of high-rises built in and around downtown over the last decade or so. Then I try to explain that, while impressive, the development downtown is really pretty exceptional, and that 96% of the city or so doesn’t allow that stuff, or anything over 4 floors or so, even i n neighborhoods where people are lining up to live, waving their money and bidding up housing prices.

Chris D.P. – The High Cost of Strict Zoning, in Washington, DC:

Across town, the Wesley Heights overlay zone strictly regulates the bulk of the buildings within its boundaries for the sake of preserving the neighborhood character. Is it ethical for the city government to mandate, essentially, that no home be built on less than $637,500 worth of land in certain residential neighborhoods?

The largest concentration of overly restrictive zoning (from an economic perspective) appears to be downtown, along Pennsylvania Ave and K Streets NW. If we value our designated open spaces, and won’t concede the exclusivity of certain neighborhoods, but understand the environmental and economic benefits of compact development, then isn’t downtown as good a place as any to accommodate the growth this city needs?

DC’s height study shows a similar pattern. The very nature of the thought exercise, the hypothetical scenarios for building taller and denser buildings in DC requires first identifying areas that might be appropriate for taller buildings. As a part of this exercise, the DC Office of Planning identified areas not appropriate for additional height based on existing plans, historic districts, etc.

These excluded areas included: all federal properties, all historic landmarks and sites; low density areas in historic districts; all remaining low density areas, including residential neighborhoods; institutional sites and public facilities. Those areas are illustrated in the Figure 4 map below. The project team determined that sites already designated as high and medium density (both commercial and residential) were most appropriate for the purposes of this study to model increased building heights because those areas had already been identified for targeting growth in the future through the District’s prior Comprehensive Plan processes.

Put this on a map, and the exlcuded areas cover 95% of the city:

Now, this isn’t analogous to the comparsions to areas zoned for single-family homes in other cities, nor are all of the areas in red innoculated from substantial physical change. However, it does illustrate just how limited the opportunities for growth are. It broadly parallel’s the city’s future land use map from the Comprehensive Plan, where large portions of the city are planned for low/medium density residential uses (click to open PDF):

The plan’s generalized policy map also illustrates the extent of the planned and regulatory conservation of the existing city form (click to open PDF):

The areas without any shading are neighborhood conservation areas.

All of this should be reassuring to those concerned about the proposed zoning changes, since all changes must be consistent with the comprehensive plan.

Fearing ‘hyperdensity’ in urban areas

Aerial view of Toronto. CC image from rene_beignet.

One of the books I picked up through the rounds of exchanging holiday gifts is Vishaan Chakrabarti’s A Country of Cities: A Manifesto for an Urban America. I’ve read an excerpt of the book published in Design Observer and watched Chakrabarti’s accompanying lecture; I’m looking forward to reading the full book.

In my initial reaction to the book’s excerpt embraced the praise for dense, urban, transit-supportive cities, but expressed concern about the political and regulatory hurdles to achieving such a vision. In particular, the ‘hyperdensity’ terminology Chakrabarti used to describe levels of density that can support subway transit seemed like it could directly antagonize citizens skeptical of change – citizens that currently hold the upper hand in many of the procedural and regulatory battles over new development.

Consider some of the reactions in Toronto. This op-ed from Marcus Gee in the Globe and Mail echoes Chakrabarti’s praise for urban density, but also shows the risk of the ‘hyperdensity’ terminology:

A spectre is haunting Toronto – the spectre of hyperdensity. Jennifer Keesmaat, the city’s dynamic chief planner, worries about it. So does one of Toronto’s smartest local politicians, city councillor Adam Vaughan…
[T]he city’s Official Plan seeks to direct new development – office buildings, condo towers and so on – to key areas of the city, fostering the process known in planners’ jargon as intensification. The aim is to put new buildings on about a quarter of the city’s geographical area, keeping the three-quarters that is left – residential neighbourhoods, quiet, smaller streets – free from runaway growth.

As anyone can see from the thickets of development around nodes like Union Station or Yonge and Eglinton, it has been remarkably successful – too successful for some. “We have reached this exciting and terrifying tipping point where we are starting to question whether it could be there is something called too much density,” Ms. Keesmaat said. “There are some areas of the city where we are seeing too much density – hyperdensity – and there are other areas of the city where we are seeing no growth at all.”

Here, the warnings about hyperdensity echo San Francisco’s concerns about “Manhattanization” – long-standing skepticism about growth and urban development with serious impacts on the city and region’s affordability over the past decade plus.

It would seem that Toronto’s plan is working exactly as intended: growth is channeled to some areas while it isn’t allowed to happen in others. Seeing little to no growth in areas of the city planned for little or no growth would all be according to plan.

This isn’t to say that the plan is wise. Trying to focus all growth in a city with high demand into downtown and a handful of mid-rise corridors might be too much of a constraint. It’s a strategy tailor-made to minimize conflict with the single-family neighborhoods, not dissimilar from Arlington County’s focus on Metro station areas while preserving single family homes nearby. It’s also one that bears a great deal of similarity to DC’s current discussions about how, how high, and where to grow. As Payton Chung notes, even this modest bargain is no guarantee to avoid conflict:

Among large North American cities, only Toronto has joined DC in making a concerted effort to redirect growth into mid-rise buildings along streetcar lines — and only as an adjunct strategy in addition to hundreds of high-rises under construction. (The two metro regions are of surprisingly similar population today.) Yet there, just like around here, neighborhoods are up in arms at the very notion.

Nor does it guarantee the city can actually match supply to demand:

DC cannot put a lid on development everywhere — downtown, in the rowhouse neighborhoods, in the single-family neighborhoods, on the few infill sites we have left — and yet somehow also accommodate enough new jobs and residents to make our city reliably solvent, much less sustainable. The sum of remaining developable land in the city amounts to 4.9% of the city, which as OP demonstrates through its analysis, cannot accommodate projected growth under existing mandates.

Something will have to give.

Toronto’s plan took the lid off in downtown, yet now the resulting development is derided as ‘hyperdensity.’ Marcus Gee notes that hyperdensity’s impact on infrastructure also provides the means to upgrade those facilities; build more transit; expand parks and urban amenities:

If the hyperdensity tag catches on, it could become a useful tool for downtown councillors who want to appease their constituents by blocking new development or for suburban councillors who want to steer more development to their wards even if there is no call for it there. It could also help kill exciting projects like the Frank Gehry-designed proposal by David Mirvish for King Street West. Ms. Keesmaat’s planning staff oppose the plan for three towers of more than 80 storeys each – too tall, too dense – and city council backed her up in a vote on Dec. 18.

It is reasonable to worry that new development will cause overcrowding on transit or overtax other city infrastructure. But if that is the concern, let’s build better transit to keep up with the growth, not halt the growth for fear of the future. Central Toronto is still far less dense than it could or should be. Hyperdensity should be a goal, not a thing to fear.

Emphasis added. This is the crux of my concern. How we frame the issue matters, even if the eventual solution won’t be about convincing the public of the virtues of hyperdensity and embracing it as a goal. Rather, achieving that goal will require reforming the processes and procedures for making decisions about land use and development.

I hope Chakrabarti’s book will touch on this; I look forward to reading it.

646,449 – DC’s population continues to grow

Cranes. CC image from Daniel Foster.

The latest state-level population estimates show another year of 2%+ growth for DC, bringing the city’s estimated population to 646,449. Former Mayor Tony Williams set a goal in 2003 of adding 100,000 new residents to the city back when the city’s population growth was essentially nil, following decades of population decline.

Even in the relatively short history of this blog, nearing the symbolic 600k threshold prior to the 2010 Census was a big deal.

Of the growth in the most recent estimates, about 1/3 of the gains are from natural increases in the population (births minus deaths), while 2/3rds are from net migration (more people moving into the city from elsewhere than moving out).

Explanations for DC’s recent growth spurt that focus on Federal government spending are tempting, but misleading. The region’s overall growth rate since World War II is fairly consistent; what’s changing now is how that regional growth is allocating itself within the region. Chris at R.U. Seriousing Me shows how DC’s share of the regional population decreased from 1950 to 2010. The region’s growth trajectory has been upward, while the District’s population declined. However, if you assumed that DC maintained the same regional share of that growth throughout the last half-century, you’d find a DC today with 2.6 million people inside the city limits.

The counterfactual scenario is intriguing: assume a DC population of 2.6 million still governed by the federal height limit, and suddenly the comparisons of DC to Paris (low-rise with high population density) aren’t so absurd. Chris notes that for those opposed to even modest changes to the height limit or the construction of by-right buildings, the kind of development needed to accommodate 2.6 million people “must sound apocalyptic.”

Leaving the apocalypse aside for the moment, the 2.6 million resident scenario illustrates that you must not only have demand for growth, but allow that growth to happen – that is, allow the city’s housing supply to increase. Again, a comparison to Paris is illustrative: the Paris region has continued to grow, while the city’s population has somewhat declined and flattened out. It’s not hard to see why; the city’s legal and regulatory constraints on development do not provide room to grow within the city.

Mayor Gray, like Mayor Williams, set an ambitious goal for growth the District’s population: adding 250,000 new residents by 2032. Unlike in 2003, it’s not hard to see the demand for city living – in fact, we’re on pace to meet that goal right now. If the city were to continue to grow by 13,000 per year (as it has over the past three) over twenty years, DC will hit that mark.

Demand is only half of the equation, however. Michael Niebauer notes that the population gains justify the increased development seen around DC, and more will be needed to accommodate increased demand for living in the city. If city does not add supply, the demand will continue to put pressure on housing prices.

Tall buildings in European cities

While visiting Europe, I missed most of the local debate on potential changes to DC’s federally imposed height limit (see – and contrast – the final recommendations from the NCPC and DC Office of Planning, as well as background materials and visual modelling, here). But I sure didn’t actually miss any tall buildings; I saw lots of them in just about every city I visited (several of which are documented in NCPC’s selected case studies).

Some thoughts on three of the cities I visited:

London:

Tall buildings emerging out of the City of London. Photo by the author.

London’s appeal for height is obvious, with skyscrapers emerging within the City of London. London has a sophisticated plan for managing heights, as explained by Robert Tavenor (transcript – slides) at NCPC’s event on building heights in capital cities (video available here), balancing London’s interest in quality of life, history, and the desire to maintain London’s status as a primary capital of the global world.

All of this planning effort focuses on the City of London, building upon the already existing transportation infrastructure while preserving specific view corridors, and ensuring that tall buildings that do break the existing skyline include high quality design and are clustered together in designated districts. Other such clusters exist outside of London’s center, such as Canary Wharf – more akin to the kind of cluster of tall buildings along the city’s periphery, as seen in La Defense outside of Paris.

Paris:

View towards La Defense, from the top of the Arc de Triomphe. Photo by the author.

View of the flat skyline of Paris from atop the Pompidou Center. Photo by the author.

Paris features a suburban cluster of skyscrapers, while the central city skyline remains almost uniformly flat. However, in recent years, the city has allowed taller buildings in the outer arrondissements. Socialist city officials pushed for additional height as part of a plan to increase housing supply and address housing affordability.

Comparing Paris to DC is superficially appealing. Paris’s almost absolute 37m limit (approx 120 feet) is similar to DC’s limit. NCPC’s summary of case studies highlight their lessons learned from Paris:

Paris demonstrates that restrictive building height controls can coexist with significant residential density. Among the case study cities, it has the greatest population density per square mile.

While this is true, it only highlights what is possible with a Parisian-style limit on height; it does not address what is required to achieve such residential densities. Payton Chung offered these comments on this blind spot in DC-Paris comparisons:

One oft-repeated line heard from the (small-c) conservative crowd is that height limits have worked to keep Paris beautiful. That comment ignores a lot of painful history: the mid-rise Paris that we know today was built not by a democracy, but by a mad emperor and his bulldozer-wielding prefect. As Office of Planning director Harriet Tregoning said in a recent WAMU interview, “Paris took their residential neighborhoods and made them essentially block after block of small apartment buildings… if we were to do that in our neighborhoods, we could accommodate easily 100 years’ worth of residential growth. But they would be very different neighborhoods.”

…

That path of destruction is why most other growing cities in this century (i.e., built-out but growing central cities, from London and Singapore to New York, Portland, Toronto, and San Francisco) have gone the Vancouver route and rezoned central industrial land for high-rises. This method allows them to simultaneously accommodate new housing, and new jobs, while keeping voters’ single family houses intact. By opposing higher buildings downtown, DC’s neighborhoods are opposing change now, but at the cost of demanding far more wrenching changes ahead: substantial redevelopment of low-rise neighborhoods, skyrocketing property prices (as in Paris), or increasing irrelevance within the regional economy as jobs, housing, and economic activity get pushed further into suburbs that welcome growth.

Another superficial point of comparison is in the effective height limit. While Parisian heights are capped at 120 feet and DC heights commonly max out at 130 feet, the exact mechanism for calculating those hieghts matters a great deal. The DC method, based on street width (height and street width in a 1:1 ratio, plus 20 feet), makes use of the extraordinarily wide streets provided by the L’Enfant Plan.

Paris has similarly broad avenues, but those avenues were carved through the existing cityscape (people often forget that the 1791 L”Enfant plan pre-dates the Haussmann renovations of Paris by half a century), and the absolute nature of the height limit allows for max-height buildings along the city’s narrow, medieval streets – with building height to street width ratios far in excess of DC’s 1:1 +20′.

Narrow streets on the Left Bank in Paris. Photo by the author.

Utrecht:

Tall buildings emerging adjacent to the Utrecht Centraal rail station. Photo by the author.

Utrecht Centraal is the busiest rail station in the Netherlands. Thanks to the city’s location in the center of the country, frequent and fast rail connections are available to all points in the country. For pedestrians, the only connection to the medieval center of Utrecht is by walking through the 1970s-era Hoog Catharijne shopping mall. The entire station and adjacent areas are currently in redevelopment, upgrading the rail station to handle increased passenger volumes, restoring a historic canal, and providing room for new, tall development adjacent to the station.

Utrecht is not the only city in the Netherlands pursuing such a strategy. In Amsterdam, the Zuid and Bijlmer Arena stations feature substantial development and tall buildings; Rotterdam’s Centraal station is also a hub for a massive redevelopment project.

According to the Utrecht station area master plan, large areas around the station provide for a base height of 45 meters, with towers up to 90 meters (~300 feet), including the Stadskantoor pictured above. Even with that height, you rarely get a sense that such tall buildings exist. The city’s narrow streets (even with short buildings) constrain view corridors. Within the medieval city, the views you do see are mostly of the 368 foot tall Dom Tower, not of the buildings of similar height closer to the train station.

More on height limit trade-offs – listening skeptically, reaching resolution

London Skyline. CC image from Elliot Brown.

One dynamic that comes up in DC’s height limit debates is the tension between gains and losses, impacts on the city and benefits to it. New development can clearly add value, but the question is if that value is a mere ‘give-away to developers’ or if citizens (the eventual consumers of that real estate) benefit from robust markets for that product. Likewise, value-capture methods open doors to finance new infrastructure, while others worry about the ability of a city to handle the strain of new development.

This tension raises a couple of issues. Kaid Benfield talks about “softening urban density” in an NRDC article. (though, as Cap’n Transit notes, the same article was re-titled by Atlantic editors as “The case for listening to NIMBYs“) The core argument is the same. While development of the city has large, aggregate benefits, there are indeed local impacts, often perceived as negatives. Benfield discusses several ways to mitigate those negative impacts, ‘softening’ their effect.

While the outcomes of softening are well and good, the real battle is not about how to mitigate impacts of density, but whether it should be allowed at all. In that context, the process for addressing those impacts is important. As Cap’n Transit notes (using the Atlantic’s title for Benfield’s piece), there is a case for listening to NIMBYs – but with a healthy dose of skepticism.

Here’s the problem: NIMBYs lie. They don’t all lie, and they don’t lie all the time, but enough NIMBYs lie often enough that you can’t just take their word for things. They don’t just lie to other people, they lie to themselves. Of course, developers lie, too, and planners lie. We’re all people.

NIMBYs are also irrational. Just like developers and planners and crazy anonymous transit geeks. We’re all people.

Seriously, how many NIMBY Predictions of Doom have you heard? Things that made absolutely no sense? But when you looked in the person’s eyes as they stood at the mic in the community center, you knew that they really believed that removing two parking spaces would lead to gridlock, chaos and honking twenty-four hours a day. And then the two parking spaces were removed, and there was no increase in gridlock, chaos or honking, but the person has never admitted that they were wrong. Somebody, somewhere should make a catalog of these crazy predictions.

We should listen to NIMBYs, not because that’s how you get things done, but because they’re people. People deserve respect, and one of the best ways to show respect is by listening. But listening and acknowledgment do not necessarily mean acceptance or agreement. We need to listen skeptically.

I’ll go one step further: it’s not just about listening, but about having a process in place to address these impacts and assess the validity of these claims – a process to apply a skeptical eye and reach a resolution.

Over in London, architecture critic Rowan Moore is casting a skeptical eye on London’s growing skyline, decrying a shoddy process with (to his eye) substandard results.

Almost all forms of resistance, such as the statutory bodies that are supposed to guide the planning system, have been neutralised, leaving only little-heard neighbourhood groups to voice their protests. All of which, if these tall buildings were making the capital into a great metropolis of the 21st century, might be a cause for celebration. Towers can be beautiful, and part of the genius of London is its ability to change, but what we are getting now are mostly units of speculation stacked high, garnished with developers’ ego. They are invitations to tax evaders to park their cash in Britain.

Of all the arguments in favor of removing DC’s height limit, the idea that it somehow stifles good architecture is the one I find least compelling. I love skyscrapers, but I also love good urban design and a city as an organism, an economic cluster, that functions in a healthy way. The mere fact that some of London’s new towers might not be the most compelling designs doesn’t strike me as a reason not to build up, as many of DC’s stunted buildings aren’t compelling, either.

Some of the same arguments about the capacity to absorb such development also come up: ” It is doubtful, for example, whether Vauxhall is a major transport interchange of the kind that the London plan thinks is right for tall buildings, but it is becoming a mini Dubai nonetheless.” Moore does mention the prospect of capturing the value of new development to fund new infrastructure and London’s Community Infrastructure Levy to help fund Crossrail, but Moore remains skeptical:

It doesn’t help that boroughs such as Southwark and Lambeth are unlikely to be tough on new towers, as they can order developers to contribute “planning gain”, which is money to be spent on affordable housing elsewhere in their territory. Livingstone liked them for similar reasons, as well us for the special delight that skyscrapers seem to have for mayors. Johnson is likely to be influenced by the community infrastructure levy raised on new developments, which helps pay for the Crossrail project. Of course, affordable housing and public transport are good things to have, but thoughtless plunder of the city’s airspace is not the way to pay for them; by the same argument, we could build on parks or on the river.

Building on parks is veering into Cap’n Transit’s above-mentioned NIMBY prediction of doom for the removal of two parking spaces.

Just as there is a simple elegance to tying congestion pricing to transit funding, there is also a simple elegance in tying the value of a growing city into the infrastructure that supports it – and it need not be dismissed as “thoughtless plunder.” Instead, our processes should identify the impacts and seek to mitigate them rather than freeze a city in amber, never to be touched. Participants should shape the result, not veto it.

Aligning our institutions and legal mechanisms to that end is a challenge. The latest piece from George Mason’s Center for Regional Analysis on DC’s housing pinch looks at some of those problems. The existence of impact fees (in the abstract) does indeed add to the cost, but so long as those fees are addressing actual impacts, that shouldn’t be a major concern. The challenges of coordinating approval processes and dealing with local opposition, however, are tremendous obstacles. That is where the need to listen skeptically is quite clear.

DC height limit trade-offs, part 2

DC skyline. CC image from James Calder

Continuing on the discussion of DC’s height limit (and potential changes to it), I wanted to take note of a few more articles on the subject. George Mason law professor David Schleicher (he of land-use law and procedure fame) asks height limit proponents six basic questions, all of which more or less ask proponents to weigh the trade-offs – or explain why they think the trade-offs do not exist. The six questions:

Do you believe supply is important in determining prices in housing and office markets?
Why do you think development should be spread out?
What effect do you think limiting heights has on agglomeration, including the depth of local markets and information spillovers?
Why do you think D.C. will grow without going up?
Do you think D.C. would instantly become as tall as New York upon repeal?
How much is the D.C. aesthetic worth?

All good questions. So much of planning work is about discussing these trade-offs; an honest discussion of the costs is a prerequisite.

One comment on numbers 5 and 6: DC can indeed go taller while still maintaining the aesthetic of a ‘flat’ skyline, if that is something of value to residents (and therefore worth the cost). The height limit’s maximum and the flat nature of DC’s skyline are two separate things; if DC’s height limit were set at 200′, we could expect buildings to eventually fill that envelope with numerous buildings up against that limit, rather than form the wedding cake shape of many other American skylines.

Indeed, if that flat-ness is what we value, then we shouldn’t fear adjusting the heights upward – opportunities to shape the city will still exist.

I also wanted to highlight a comment in Kaid Benfield’s original Atlantic Cities piece from ArtR:

1) at current demand for jobs and housing DC has at least a 30 year supply of land to add over 200,000 more jobs and 169,000 people without changes to zoning or the height limit (DC Office of Planning).

I don’t doubt that this is true, but the question of how much land is available gets back to the old real estate cliche of location, location, location.

2) Density through high rise steel and concrete construction will not increase housing affordability. Hard costs alone are over $200/sf with soft cost, land and profit you are well over $400/sf and with even minimal parking you are over $500/sf, thats $500,000 for a small two bedroom. To the extent high-rises syphon off high-income households that might stabilize less costly forms of housing but I am skeptical.

Art is making two points: one about costs, and one about filtering within the market. In terms of costs, Art is absolutely right – relaxing the height limit will not magically lower construction costs. However, couple that reform with others (such as the aforementioned reduction in required off-street parking) as well as efforts to speed approvals and reduce the lead time required for building and we’re on to something (all potentially positive outcomes of DC’s zoning code review).

The point about filtering is trickier. Certainly, in the abstract, adding more supply should relieve pressure on older housing units to filter up to more expensive submarkets, but the key phrase in all such abstractions is “all else being equal.” All else is clearly not equal, and I can’t blame someone for skepticism on the ability for upzoning to make this happen – particularly when such changes to the zoning code happen on an ad-hoc, case-by-case basis.

3) There is a difference between capacity and supply. Raising the height limit may increase capacity but it does nothing for supply. Supply is a function of developers meeting demand and development stops the instant prices stop rising.

While this point is also true, the nature of the equilibrium depends on the other factors influencing cost. For example, take the examples from Portland, where the elimination of on-site parking requirements allows some development to pencil out a lower price point.

There’s also a point to be made here about location. If our goal is to add supply, the market might be able to support a lot more supply in more desirable locations. However, if most of the District’s developable capacity (in point 1 above) is not in those locations, then it will take something else to turn that capacity into new supply.

4) There is nothing to suggest that height alone will increase demand. In fact, too much capacity can increase uncertainty because you never sure how much your competitor can absorb. Denver learned this when they down zoned neighborhoods and they took off.

I hope no one takes away the idea that changing the height limit alone will lead to some magical change in DC’s built environment. Given the fact that zoning is usually an even greater constraint (and given the procedural challenges it can impose), it shouldn’t be seen as a panacea.

Height limit trade-offs

The Cairo. CC image from NCinDC.

Following up on some of the trade-offs mentioned at the end of the previous post on DC’s height act.

In the discussion of Kaid Benfield’s piece supporting DC’s height limit, several comments are worth highlighting. First, Payton Chung notes the need to discuss more than just supply, but to also realize the strength of the demand for living in DC:

I think that a splendid city could be built within the current Height Act, or a revised one, or perhaps even none at all. However, I’ll raise a few counter-factuals, recognizing that I also have not gotten around to writing more extensively about the topic:

1. The growth projections for this region are staggering: +874,394 households and +1,625,205 jobs from 2010-2040. Yet your (and my) preferred strategy of retrofitting mid-rise corridors has a limited upside. Toronto’s Avenues plan, which promotes redeveloping its extensive streetcar commercial strips with a 1:1 street enclosure ratio (building height=street width), only projects an additional 2,000 residents (=1,000 units) per mile of redeveloped “avenue” frontage. Given the District’s small footprint, that’s not going to be enough to absorb very many new residents, much less to increase the city’s housing stock by enough to improve housing affordability.

2. As you well know, a huge difference between Washington and the world’s great mid-rise cities (not just the European capitals, but also cities like Buenos Aires and Kyoto) is that Washington’s mid-rises peter out into single-family houses just one or two miles from the core, while those cities have multifamily-density housing stretching clear to the city limits. This brings me to your point about creativity: what high-rise downtowns do is to concentrate high-value uses within a small area instead of letting it spill out into neighborhoods. High-value office, hotel, and retail uses have priced out most of the creativity in Dupont Circle, Woodley Park, Georgetown, Mount Vernon Square, etc.

Toronto’s Avenues planning study can be found here, and the report’s executive summary is here. This kind of development is excellent infill and definitely worth pursuing for many cities (not just those with height constraints like DC). Still, the constraints are real and the opportunity for this kind of infill is limited, however promising it may be.

On Twitter, Neal Lamontagne takes note of the positive abilities of regulations to shape urban development, and the need to balance against their costs:

[link] @ryanavent Agree, but – limits also linked to + land values. Still, not only economic but also design arguments. Better to shape than squish

Another comment from Payton, making note of the trade-offs in accommodating growth in other areas of the city:

In theory, it should be possible to significantly increase population and jobs within the District and not raise the existing heights. However, the city isn’t exactly littered with vacant lots; such increases would require a lot of demolition, and a lot of density within existing single-family neighborhoods.

Household sizes are *dramatically* smaller than they were: even though the city’s population dropped by 184,000 over the past 60 years, the number of housing units increased by 70,000. Much of that change came from carving up single-family houses into apartments, which is now much more controversial than it used to be.

Under the new Sustainable DC Vision, the city will need over 100,000 new housing units over just the next 20 years. Accommodating more households within the more location-efficient city will, as you know, reduce the region’s ecological footprint. But I genuinely wonder where these units can go: as I mentioned, due to the city’s small size there’s only 3-4 miles of redevelopable land along key arterials like Georgia, Rhode Island, and East Capitol — I’d add some in Upper NW, but you and I both know that’s highly unlikely — and those are only sufficient to address 10% of the total housing demand.

The real reason why Vancouver went whole hog for downtown skyscrapers was not about views, not about impressing people; it was about accommodating dramatic population growth while leaving its single-family neighborhoods mostly untouched, after a citizen revolt over “secondary suites” (accessory units). I know that my neighborhood is (mostly) ready for a few thousand more, perhaps even several thousand more, but is yours?

The point about feasibility is important. It just might be easier to go to Congress to change the height limit than it would be to fight a million NIMBY battles in established neighborhoods. There’s a case to be made for more of that type of development to be allowed by-right, but that too represents a big change.

Some of the trade-offs will involve resolving tensions within the urbanist community. On Twitter, in response to Ryan Avent’s frustrations, Yoni Appelbaum notes:

[link] @ryanavent First-wave urbanism was fundamentally nostalgic. Redevelopment was the threat, and revival the solution.
[link] @ryanavent It’s less an allergy to empiricism than an exposure of the simmering tension between that nostalgia and more progressive visions.

Payton again, asking rhetorically where this mid-rise development will go:

Again to the last two commenters: how do you propose to add mid-rise density without demolishing huge swathes of low-rise buildings, either in the District or Arlington? Already, rowhouse neighborhoods like Chinatown, Foggy Bottom, Southwest/L’Enfant Plaza, the West End, and now Navy Yard and NoMa (particularly its eastern flank) have been sacrificed to extend the medium-rise downtown. Facadectomies are the only way that we have to remind ourselves that these were indeed low-rise at one point in time. Which neighborhoods should be demolished next for the growing downtown?

@tassojunior: we live in small enough apartments already — we have to, what with a median sales price of almost $500/square foot!

Payton, (again!), this time in a thread at Greater Greater Washington:

The problem is not with mid-rise densities, it’s with low-rise densities. I would be happy, perhaps even elated, to see mid-rise densities spread across a wide swathe of Washington, D.C., but I know that many others would not. Indeed, they, including many of Kaid’s neighbors in Ward 3, are already in open revolt, with dire consequences for the city, region, and planet.

You can’t squeeze a fast-growing balloon on the sides (protecting low-density neighborhoods) and the top (height limits) forever.

Bold is mine, and it’s spot on.

Bad reasons to support DC’s Height Act

DC Skyline. CC image from Ed Uthman.

DC’s lack of tall buildings is certainly one of it’s defining characteristics. Given our human tendencies to be loss averse, to embrace the status quo, it shouldn’t be a surprise that changing such a characteristic can be shocking to some.

I’ve written on the height limit before, as have many others. The most recent defense of the law comes from Kaid Benfield (both at the NRDC and Atlantic Cities). Kaid outlines some good qualitative reasons to embrace the limit – unfortunately, marred by some of the serious shortcomings and logical fallacies from his other arguments in support of the limit. I share Ryan Avent’s frustration with some of the manners of argument.

As an example, some of the arguments Kaid presents in favor of the height limit, and a brief response:

Actually, DC can grow under current law. In 1950, with the height restrictions fully in effect, the city’s population was 802,178. In 2011, its estimated population was 617,996. The truth is that we were a “shrinking city” until about a decade ago, and we are nowhere near full capacity today.

It is misleading to call DC a ‘shrinking city’ solely based on population, as that description misses several confounding variables. One is household size: it has been steadily decreasing over time (averaging 2.72 persons per hh in 1970, down to 2.16 in 2000), meaning fewer people occupy the same amount of space. Furthermore, DC has indeed grown – it has more housing units than it did when its population peaked, and it has more jobs, too (and thus more office space).

So, no – the fact that DC’s population is lower today than in 1950 does not suggest the city has excess capacity.

A lot of other things are going well under current law, too. As Derek Thompson wrote in The Atlantic, Washington is the richest and best-educated metro area in America, leading the nation in economic confidence.

I don’t know that being rich proves success. In fact, there’s plenty of evidence that areas like DC and SF are so rich because they are exclusive, and that high prices prevent the middle class from paying reasonable prices for housing. Ryan Avent has written on this extensively. Simply put, more wealth is not the sign of a healthy economy.

Building height has little to do with affordability. The argument that a limit on building height restricts housing supply and thus leads to higher prices is essentially the same argument made against Portland’s urban growth boundary. In both cases, it’s hogwash: if affordability were closely related to building height and density, New York City and San Francisco would be the two most affordable big cities in America.

This one is just absurd. No one is proposing increasing building heights in DC just for the sake of going taller; the entire reason to change them would be to remove a constraint to growth. The constraints to growth do indeed have costs. Portland’s UGB is also a constraint. Constraints do not need to be a negative if there are other means to allow growth; then they can shape that growth instead. But to imply that elevation alone is the key to affordability is absurd. Asserting those who would change the height limit believe such absurdity is beyond reason.

In any event, denser doesn’t necessarily mean taller. These numbers may surprise you: Barcelona is denser than New York City, housing 41,000 people per square mile compared to New York’s 27,000. Barcelona’s beautiful and thriving, mid-rise central district L’Eixample is denser than Manhattan, at 92,000 people per square mile compared to Manhattan’s 71,000. It does not have buildings taller than Washington’s. In D.C., we could increase density substantially by incrementally converting many aging one- and two-story buildings in commercial and mixed-use districts to a still-human three to five stories.

The comparison of DC to Paris drives me nuts. Paris is indeed dense, and mostly low-rise. However, Paris has little of the small-scale rowhouse and single family homes that populate DC’s neighborhoods – if DC were Paris, those areas would be built out with 5-7 story apartments.

Yes, DC could likely increase density to Parisian levels and remain beneath the limit; but people seldom note what would be required to make that happen, what the trade-offs would be. Would DC residents trade the complete redevelopment of its historic rowhouse neighborhoods for that to happen? Benfield does not discuss the trade-offs.

One of Ryan Avent’s chief frustrations is a failure by height limit proponents to acknowledge the costs of the policy. Ryan makes an estimate of those costs in his blog at The Economist:

Even simply taking the 22% figure, we’re left to conclude that the policy is extraordinarily costly. It represents a sigificant transfer of income from renters to homeowners. It represents a rise in the cost of business for all those operating in the area (which translates into more expensive government, as the impact of high housing costs on real wages forces the government to pay higher nominal salaries to attract qualified workers). And it captures the stultifying economic effect of crowding out in the Washington-area economy, as relatively location-sensitive activities (effectively, those not conducting business with the government) are driven out of the District into the suburbs or other metropolitan areas.

Regardless of what the actual cost is (and another Atlantic Cities piece quibbles with Ryan’s calculations), it is clear that the cost is substantial. And, as the case of the Portland urban growth boundary mentioned above notes, there can be good reasons to have these constraining policies in place. Avent continues:

There is a more practical case for limiting development, namely, that as Washington becomes more dense there will be negative spillovers accompanying the positive ones: more traffic, for instance, and more noise. Such costs aren’t negligible and often help explain NIMBY attitudes. Yet these shouldn’t dissuade Washington from making it easier to build. The net benefits of easier building should be large enough to help compensate losers and invest in projects to ameliorate negative effects.

Indeed, the discussion about DC’s height limit would be better off with a discussion of costs and trade-offs. Likewise, an acknowledgement of the fundamental truth about cities would help: the only constant is change.

City Block

a work in progress…