Thursday, July 28, 2011

Urbanism, On-Campus and Off

In  the final chapter of The Geography of Nowhere, reviewing the repercussions of the "great suburban build-out" of the past 60 years, James Howard Kunstler writes that:

"[a] further consequence is that two generations have grown up and matured in America without experiencing what it is like to live in a human habitat of quality.  We have lost so much culture in the sense of how to build things well. ..."
Although this statement might have been true enough at the time of the book's publication in 1993, since then there have been several changes in the experiences of Generation Y. One of the most notable of these has been a dramatic increase in participation in study abroad programs, almost all of them located in countries and cities where students have firsthand exposure to a car-free life in traditional urban environments.  

In the 1993-1994 academic year, only 76,302 American students studied abroad, a number that had climbed only slightly since the mid-1980s.  By 2008-2009, the number had risen to 260,327, with the result that somewhere around 2,000,000 members of the age group currently in their early 20s to early 30s have spent a substantial amount of time living abroad, most frequently in countries such as Britain, France, Spain, Italy and China.  Many thousands more leave for work or travel.  This is still only a fraction of all Americans in that age bracket, but the number is no longer insignificant and continues to rise.

Mirroring this trend is the widely-reported movement of young people to urban areas in the United States, which many (other than Joel Kotkin) have taken to represent a generational shift.  A semester's experience in Barcelona, Tokyo or Buenos Aires helps make the transition a natural one.

The greatest exposure to something resembling a traditional urban environment is much closer to home, however.  The American college campus itself remains a rare example of a community type where an attentiveness to aesthetics and something resembling formal urban design has persisted without interruption, due in large part to the fact that, except in the case of some commuter campuses, the environment is designed to favor users who will be getting around by foot or bicycle.  The notion that college students are entitled to super-convenient car access, steps from the dormitory, in most places has simply not caught on.

Although the stereotypical American campus with grassy quad and red brick buildings scattered among winding footpaths owes much more to English pastoralism and the design of places like Oxford than to the dense urbanism of, say, the University of Bologna, the campus environment has remained a walkable one, if not entirely car-free, both in urban and rural settings.

As an example, Dartmouth College, located in a small town of around 6,000 non-student residents with an overall density of only 229 people per square mile, has a population density of roughly 3,500 per square mile within the inner green circle shown below, representing a the area within a five-minute walk of the center of campus (the outer circle shows a 10-minute walk):

Although this density is generally associated with suburban areas, an almost complete reliance on foot and bicycle travel means that there is a steady volume of walkers and bikers on paths and sidewalks.  Students are allowed to bring cars onto campus, but they must be stored at a single lot, visible in the upper right hand corner of the image, that is beyond a ten-minute walk from the center.  This insures that the only car trips taken will be those for which a car is absolutely necessary – generally weekend excursions or shopping trips to nearby towns.

Strangely, the significance of this arrangement, in terms of quality of life it offers, seems to escape many students.  Speaking recently with a friend who now swears by his car, I asked whether he'd had one during his undergraduate years.  No, he said, only access to his friend's.  Did he ever use that one?  Less than once a month, for shopping runs.  Was there any inconvenience from all this?  No – quality of life was outstanding, better than he had now.  And yet, he'd hardly given a thought to the fact that he, who couldn't imagine being without his car, had lived an essentially car-free life for four full years.  The design of the campus was so self evidently well suited to walking that, as with many others, it simply hadn't crossed his mind. 

Colleges, despite being lately infatuated with "sustainability," do not typically praise the virtues of this lifestyle in their promotional materials, websites critique schools for inconvenient parking, and campus design remains driven by administration planning officials rather than an Oregon Experiment approach, so it's perhaps not all that surprising that few students dwell on this subject and its implications.

Now, if a college campus seems an unrealistic model for urban planning or even urban inspiration, recall that, from Nathan Lewis' studies of Tokyo suburbs, within the smaller green circle above it is possible to accommodate over 25,000 people entirely in single-family detached homes, a number which can support mass transit.  Attach houses together and the number could rise to 35,000 or 40,000.  Attention to design, to attractive architecture and to public spaces does the rest. Banishing cars to peripheral lots is a technique which has been successfully implemented in some places, such as Vauban, outside Freiburg, but which is for the most part untested in the United States – outside a few colleges and universities, where it appears to work effectively and without controversy.

Overall, the notion that American youth do not have exposure to traditional or car-free living environments seems to run counter to the evidence, regardless of whether students are consciously aware of this fact or not.  Whether this will lead to substantial changes in how the Americans think about density, walkability and the urban environment still remains to be seen.

Thursday, July 21, 2011

Blocks of New York

Picking up on the topic of block dimensions and street widths from where commenters left off on Monday's post, I thought I'd share what must be the strongest statement ever made on this seemingly pedantic topic, made by architect Ernest Flagg in 1894:

"The greatest evil which ever befell New York City was the division of the blocks into lots of 25 x 100 feet.  So true is this, that no other disaster can for a moment be compared with it.  Fires, pestilence, and financial troubles are as nothing in comparison; for from this division has arisen the New York system of tenement-houses, the worst curse which ever afflicted any great community." -The New York Tenement-House Evil and Its Cure
A bit overblown, but Flagg had a point.  The fundamental problem was twofold: at 100 feet long, such a lot did not permit interior rooms of a tenement to have windows if walls were shared, yet, at 25 feet wide, there was not sufficient space to create meaningful side setbacks.  The chronicle of New York's tenement laws from 1879 to 1901 shows an attempt by the city to mitigate the effects of these dimensions, which, it turns out, had been chosen by the city's own hand-picked team of commissioners in 1811 as part of the broader grid plan for New York.

And why, after all, had the commissioners chosen blocks of these dimensions?  It can't be known with certainty, but in the 1807 state law empowering the commissioners, the New York legislature (at the urging of the city) had set forth certain planning requirements: 1) that no street be less than 50 feet wide, and 2) that once the commissioners had drawn up their plan, no new streets would be opened through city blocks.  The reason for these regulations seems to have been in part, according to surveyor John Randel Jr., to "[avoid] the frequent error of laying out short, narrow, and crooked streets, with alleys and courts, endangering extensive conflagrations, confined air, unclean streets, &c."

A prohibition on alleys, however, required that all blocks be fairly narrow, since interior block space in wide blocks, without alley access, would be distant from the street and have little economic value.  But the commissioners could not go too narrow either: due to the minimum street width requirements, a city with square blocks much less than 200' would have as much as 50 percent of its land area occupied by streets – a poor outcome for commissioners concerned with maximizing the amount of land for sale to private buyers. 

The resulting blocks of 200 x 800 were therefore an awkward compromise, as an attempt to keep blocks narrow enough such that the amount of inaccessible interior block space was minimized, while maximizing the ratio of buildable to non-buildable area by stretching the blocks out lengthwise.  In no other American city are similar blocks found, possibly due to the fact that in all, or nearly all other cities, alleys were not prohibited and could be called upon to open up overly large grid blocks.

San Francisco street map, showing narrow streets bisecting
grid blocks and reducing block widths to 150' and in some
cases as little as 100'.
Following the establishment of the initial plan, blocks were subdivided into individual lots by property owners, with a common dimension being 25' x 100'. Although Flagg writes that "[w]hen the city was first laid out, the division of the blocks into lots 25 x 100 ft. was entirely unobjectionable," as "people generally built houses of moderate dimensions, lighted at the front from the street, and in the rear from the yard," once land values rose – which did not take long – the deep lot provided a strong enticement to construct houses in the rear, notwithstanding the lack of street access.  Pre-law tenements soon followed, making the most profitable use of the blocks which the city had parceled out in the thousands to private developers.  The lot sizes, moreover, although presumably laid out with a single family in mind, actually contained an inherent bias against single family homes: since a rowhouse might only need 40' or 50' of depth, the creation of lots of 100' length, while prohibiting alleys, essentially made the construction of modest rowhouses an uneconomical proposition.

In the end, the intent of the city to avoid "unclean streets" and "confined air" by banning both new and narrow streets had led, in a lengthy causal chain, to the most filthy, cramped, darkest and least ventilated building type found anywhere in the United States – an urban form so dire that it ultimately contributed to a backlash against the entire notion of a dense urbanism of attached, street-fronting dwellings, and gave inspiration to the tower-in-the-park form which characterizes many or most public housing projects in New York.  The commissioners could never have forseen this outcome, but the lessons, as far as the importance of block and street width, are definitely worth thinking about.

For a some good background on all this, check out Columbia's series on New York apartments here.

Monday, July 18, 2011

New World Economics on Single-Family Solutions

Nathan Lewis' latest is now available: How to Make a Pile of Dough with the Traditional City 4: More SFDR/SFAR SolutionsNathan addresses the very basics of urban form: the relationship of block depth to street width, lot dimensions, and accommodating cars into a dense urban fabric.  Feel free to leave comments about it here.

One underlying point is similar to the one I made in last week's A Tale of Two Densities: to create a neighborhood that is both 1) mainly single-family, attached or detached, and 2) is dense enough for walkability, blocks must be shallow, and if blocks are shallow, streets must also be narrow, or else the ratio of street to built area will be much too high, and density will suffer.  This pattern is reflected is most all organic city growth, where blocks are commonly around 100 feet across, and rarely more than 200. 
Beaucaire, France: narrow streets and narrow blocks.

Friday, July 15, 2011

Friday Reads and Links

Much of Besim Hakim's published work, a highly recommended read for anyone with the slightest interest in emergent urbanism, urban history and architecture, is available here (additional links at bottom of page) and is now added to the permanent links.  More to say about his work in future posts.

Murcia, Spain, offers to accept cars in exchange for lifetime transit passes.  I'd had the chance to visit Murcia, and if there's a country with an overall better and more livable urbanism and urban tradition than Spain, I'd like to hear where it is.

Old but still relevant: Ivan Illich's observations on walking, cars, bikes and the transportation industry.

The front lawn story out of Oak Park has sparked some critical reflection on the American front lawn from a variety of quarters.  Time's Brad Tuttle observes:
"...Space hogs, water suckers and giant leaf collectors that have to be blown, mown and doused in chemicals with a great ruckus to look good, what is the point of a lawn other than to say: we have land, time and money to waste?"
Scrutinizing Seattle's setback requirements, Seattle's Land Use Code asks:
"But I do wonder why do we require yards anyway? Shouldn’t we treat yards like parking? If people want yards then they can pay for them. Why build that in to requirements? ... Yards should be next on our list after parking in terms of code reform."
Chuck Wolfe has a thoughtful article on lawns which graciously links my earlier piece on the American front lawn.  Walkable Dallas-Fort Worth has more to add as well.  I've already mentioned The Case Against the American Front Lawn at Apartment Therapy and The Great (Big) American Lawn at Per Square Mile. 

Wednesday, July 13, 2011

Households v. Bedrooms

Following Alon's comment on the relationship between household and housing unit sizes in the previous post, I've put together a chart to show the distribution of unit sizes, by bedroom, in a variety of cities and other places, as compared to the distribution of American household sizes (using the most recent ACS data for housing stock):

Only the areas of cities within urban boundaries are shown.  Chester County, near Philadelphia, represents a standard suburban pattern of development, while Westport is an affluent New York commuter town. 

The idea that cities, outside the island of Manhattan, suffer from a lack of units large enough to accommodate a family of typical size seems to be disproven, although number of bedrooms is of course only one of numerous factors affecting a family's choice of location.  Otherwise, I'll leave comments and interpretations here to others.

Monday, July 11, 2011

A Tale of Two Densities

Apartments, Rowhouses and the Spatial Logic of Narrow Streets

In Hoboken, New Jersey, the fourth densest incorporated place in the United States, there is a two-block stretch between 6th and 7th Streets where the "hypertrophic" fabric of the great majority of the city, consisting of walk-up apartments and large brownstones on wide streets, abruptly gives way to a series of smaller rowhouses on narrow streets cut through a single larger block.

The five-story brick apartments lining the block to the right are the so-called tenements of the type which Jacob Riis wrote about and which menaced the Little House in the animated Disney film of the same name.  They are emblematic of New York's urban growth in the 19th century and are still abundant throughout the city. Occasionally mixed among them, up large and ornate stairways, are brownstone townhouses with garden apartments.

To the left, the standard Hoboken city block has been subdivided into three smaller blocks by use of two narrow streets along which, with no setback, are built a series of modest two- and three-story rowhouses more typical of Philadelphia or Baltimore than the New York area.  The apartments across the street tower over these small houses, certainly giving the visual impression of much greater population density:

The stark juxtaposition of these characteristic urban forms virtually begs a comparison of the densities in play here.  Since population figures aren't available, I use the objective substitute of bedrooms instead, counting northwards from where the rowhouses begin:

Rowhouses: 2.5 blocks of 32 rowhouses each = 80 total units
80 x 3 bedrooms apiece = 240 bedrooms

Apartments: 17 apartments (10 and 8 unit) + 13 brownstones (2 unit) = 182 units
182 units x (169 1br + 13 4 br) = 221 bedrooms

So, despite the height advantage of the apartments, the rowhouses actually contain a slightly greater number of bedrooms, due mainly to 1) the spatial efficiencies of having multiple bedrooms per unit, compared to one bedroom units, and 2) the narrow streets, which by subdividing the block more than double the number of street-fronting rowhouses which can be accommodated in the same space.  Adding street frontage has the potential to add both value and density to the land, but is dependent on the use of narrow streets lest the benefits be canceled out by the loss of space to new rights-of-way.

Consider also that while 3 bedroom units are capable of hosting both families and individuals (as roommates), the typical American family will find it intolerable to live in a studio or one bedroom apartment as their immigrant forebears did, no matter what urban amenities are nearby.  Given that family households, averaging 3.2 persons each, continue to outnumber non-family households more than 2-1 in the United States, the rowhouses are better suited to contemporary American demographics and living preferences. 

One option for the apartments, rather than building higher, would be to simply combine one-bedroom units on each floor to create larger 2 or 3 bedroom units (resulting in a decrease in the number of units, but an increase in the number of bedrooms*).  An older New York Times article describes this process, the economics indicating a severe mismatch between supply and demand for larger apartments in New York:
"A two-bedroom apartment priced at $450,000, when added to a one-bedroom apartment priced at $250,000, could easily be appraised as a new four-bedroom apartment worth $1 million, a relatively painless way to increase value by almost half.
Broker after broker offers stories of combinations that typically increased value by 30 percent to 50 percent, relating the details as if they were prospectors in a new gold rush. In one instance, a mortgage broker says, a client put together five studios at a cost of $1.1 million that when renovated were appraised for $2.7 million."
The pattern seems to hold true in Hoboken, as well, given that a renovated rowhouse on the block pictured recently sold for $727,000,  far above Hoboken's mean of $417,000. 

As for overall population density, a neighborhood built of such rowhouses could potentially exceed 50,000 people per square mile, assuming one person per bedroom.  This is a density comparable to Paris and higher than Brooklyn or the Bronx.  If higher densities are possible, they may not necessarily be desirable for various reasons relating to infrastructure, transportation and overall crowding.  All this is not to advocate for a particular type of urban form, though, but as one more way to think about the issue of street width, building height and density.

*This has implications for the usefulness of the "units/acre" metric for density, which will tend to reward neighborhoods of one-bedroom units while penalizing those with more multi-bedroom units.

Related Posts:
Glazer v. Glaeser on Density
Skyscrapers, Height and Density
Can New York Build Its Way Up To Affordability?
More On Density

Wednesday, July 6, 2011

American Front Lawn Update: Turf Wars

Back in May when I put together a post on setbacks and the American front lawn, I wrote that cost, social pressure or concerns about resale value would tend to discourage homeowners from considering creative alternatives to a grass lawn.  To that list must also be added force of law, judging by this story out of Oak Park, a Detroit suburb, where the municipal government has confronted a local homeowner who decided to turn her front lawn into a vegetable garden:
Code enforcement gave her a warning, then a ticket and now she's been charged with a misdemeanor. ... "That's not what we want to see in a front yard," said Oak Park City Planner Kevin Rulkowski. Why? The city is pointing to a code that says a front yard has to have suitable, live, plant material. The big question is what's "suitable?" ...

"If you look at the definition of what suitable is in Webster's dictionary, it will say common. So, if you look around and you look in any other community, what's common to a front yard is a nice, grass yard with beautiful trees and bushes and flowers," [Rulkowski] said.
While the planner's comment plainly gives away the conformist and aesthetic rationale underlying these particular regulations, this disagreement is one which again can only be fully understood in the context of setback requirements.  Under Oak Park's zoning ordinance, all single and two-family residences must be set back at least 25 feet from the street, of which 20 feet must remain as "open space unpaved, unoccupied and unobstructed from the ground upward." 

When combined with the city's interpretation of its code, this requirement places an affirmative duty on all homeowners to maintain ornamental front yard plantings in perpetuity.  The homeowner may comply either 1) by dedicating her leisure time to lawn maintenance, without compensation; or, if the financial means to avoid this are available, by 2) compensating others to maintain her property (simultaneously a hidden property tax and a generous subsidy for the local landscaping industry).

The Oak Park homeowner in the article, in essence, rejected option 2) and instead attempted to earn  a type of compensation from the labor required of her in option 1).  This, in Oak Park, as in many other suburban jurisdictions and HOAs, is an offense against codified majoritarian aesthetics and apparently may be criminally punishable. Once front-yard farming is decriminalized, however, the market finds ways means of making these yards economically productive – such as in Vancouver, where private yard-farming firms cultivate vegetables on home lawns, with part of the crop going to the homeowner and the remainder to local CSA groups. 

Still, the pro-urban farming perspective seems to address only part of the main issue here, which (for me at least) is not should we also permit gardening in front yards?, but why should we at all limit the reasonable uses to which the front 25+ feet of the property is put (up to and including building on it)?  The front setback's origin, purpose and continued reason for being, as I've tried to show, is precisely to work in tandem with landscaping codes to mandate an uninterrupted field of grass lawns in front of all homes.  When the setback is divorced from this underlying goal, what justification can be given for requiring it? 

This is perhaps why a homeowner turning a front yard into a garden is so significant: it subversively challenges the rationale of a key element of the mandated American suburban form, poking a finger in the eye of William Levitt and the authors of a thousand suburban zoning ordinances.

Other lawn-related posts from here and there, highly recommended:
The Case Against the American Front Lawn at Apartment Therapy (thanks for the link!)
The Great (Big) American Lawn at Per Square Mile

Tuesday, July 5, 2011

Slums, Titles and the World's Simplest Zoning Code

Although from the perspective of a resident of the United States, Canada, Western Europe or a handful of other countries, the organic pattern of city growth might seem to be a historical bygone, visible only in those portions of cities developed before the late 17th century, the last 50 years have in fact produced the greatest wave of emergent urbanism in human history.  This growth, reflected in the so-called slums of South and Central America, Africa and Asia, utterly dwarfs in scale any formally-planned public housing built during that time, and currently houses between 1 and 1.4 billion people worldwide.

"Slum" (Rio De Janeiro) and below ...
These settlements, built with virtually no guidance or oversight, produce urban environments of extraordinary complexity, beside which even the most carefully designed project can seem simplistic by comparison.  Although they are not always beautiful in a conventional sense, their astonishing variety makes them a favorite of photographers with an artist's eye and appreciation for the visual interest of a basic built form repeated in endless irregular variations across a dramatic landscape, much like the Italian Cinqueterre or the towns of the Aegean islands. 
... international tourist destination (Riomaggiore).

A New York times article, writing about the Mumbai slum that was the setting for the film "Slumdog Millionaire," describes how the visual complexity of these places is matched by their economic complexity and the resourcefulness of their inhabitants -- an inventiveness that recalls Jane Jacobs' observations in The Economy of Cities:
"Understanding such a place solely by the generic term “slum” ignores its complexity and dynamism. Dharavi’s messy appearance is nothing but an expression of intense social and economic processes at work. Most homes double as work spaces: when morning comes, mattresses are folded, and tens of thousands of units form a decentralized production network rivaling the most ruthless of Chinese sweatshops in efficiency. Mixed-use habitats have often shaped urban histories. Look at large parts of Tokyo. Its low-rise, high-density mixed-use cityscape and intricate street network have emerged through a similar Dharaviesque logic. The only difference is that people’s involvement in local development in Tokyo was seen as legitimate."
The traditional response to such settlements by city and national governments, still common today, is to evict the inhabitants and demolish the structures. Uprooting the community in this fashion destroyed the energy and scarce resources that the residents had put into their dwellings, disrupted social and economic networks, while the construction of new public housing, intended to host at least some of the displaced residents, redirected government revenue that might have been used to improve the existing settlement to building an inadequate number of units which were poorly suited for people's social and economic needs

More recently, in acknowledgment of the counterproductiveness of demolition, various South American governments, notably Mexico and Peru, have begun issuing formal titles to the possessors of slum properties.  The stated purpose of this approach, advocated by economist Hernando de Soto and endorsed by none other than Milton Friedman, is to increase tenure security and to permit the land to be used as security for business loans. 

So far, although titling of properties has led to an average 25 percent increase in land values, the promised access to capital has largely failed to materialize.  Further, the awarding of formal titles has often served as an invitation to outside real estate interests to enter the market, futher inflating prices and potentially driving out the very people whose tenure the titling program was purportedly designed to protect.  In Mumbai, this process took the form of large apartment towers sprouting in the low-rise Dharavi slum, adding height without necessarily increasing density (in any event population density in these areas appears to be exceptionally high even in the absence of buildings over three stories).

An alternative approach, adopted mainly in the Brazilian city of Recife, has been to provide tenure security not with titles, but by recognition of the community's claim to the land, combined with the implementation of what is perhaps the simplest zoning code to be found anywhere in the world: 1) a two-story height limit; and 2) a maximum lot size of 150 square meters (1,615 square feet).  Informal exchanges of property, without deed recording or title transfer, continue unhindered, reducing transaction costs and encouraging an extremely flexible urbanism where boundaries and structures rapidly adapt to changing needs. 

Mathieu Helie argues that the remarkable organic form of these slums is dependent on this openness -- an attempt to make them conform to a particular notion of property rights (that of individual freehold ownership by way of titles, deed recording and plat maps) is to deprive it of the flexibility that allowed it to take shape in the first place:
"After praising slums for their ability to generate economic opportunities, they are denounced [by a City Journal article] for not fitting into the conventional model of property rights. Yet it is precisely the use of more natural methods of property allocation that gives slums their organic morphology. ...

"Just like we can’t make the organic morphology of slums fit into the modern rules of property ownership, we can’t make traditionally emergent cities through the current planning system. (All efforts to produce traditional neighborhoods have so far produced only imitations of them.) ..."
The question of how to produce such traditional or emergent environments in a developed country in the present day is one which people such as Christopher Alexander have devoted their careers to, but answers, in practice, remain elusive.  The example of places like Recife does suggest the answer could be simpler than ever imagined.

Sources and Additional Reading:
Urban Land Tenure Options: Titles or Rights?
Regularization of Informal Settlements in Latin America
Secure Tenure in Latin America and the Caribbean
The Role of Urban Slum Titling in Slum Improvement