Monday, June 28

A garden block proposal

It looks like one of the main take-aways from the CNU 18 conference is something being labeled agrarian urbanism. Fast Company is calling it the "new new urbanism" and Treehugger has described the notion as the next phase in the evolution of this 30-year old movement. Andres Duany, in particular, has been pushing pretty hard in this direction for the last couple of years. Briefly, the idea is that walkable neighborhoods could be intentionally structured so that food production is integrated into the physical form and the lifestyle of the inhabitants. In other words, it is a synthesis between urban and rural.

Of course, this new new urbanism is really no newer than the old new urbanism was (but that's fine). One of the primary motivations behind Ebenezer Howard's Garden City was to connect working class households with a viable food supply to relieve some of their financial stress. He landed on the number twelve dwelling units per acre as the magic density for self-sufficiency with affordability, and he worked out a form of common land ownership to help it along. Christopher Alexander thought that something more like a tenth of an acre was necessary to supply vegetables to a family of four. He had plenty of practical, timeless advice for arranging an urban living space accordingly. More recently, some architects have been using the word rurbalization to describe this sort of synthesis. Having recently passed through the grad school circuit myself, I can attest to a strong interest in food systems among new graduates.

I think these are good trends. Local food systems should inform urban design and vice versa, but I'm not sure the new developments being modeled have been able to find this synthesis without swallowing one side with the other - specifically, subsuming the urbanism into the bucolic landscape. This seems to be the case with Southlands in British Columbia and Serenbe in the exurbs of Atlanta. Kaid Benfield has this to say about these "farming is the new golf" developments,

"In theory, these "new towns" are great - self-contained entities providing walkability, efficiency, and all the services of a community within the development.  So, their proponents (nearly all of whom profit from them, one way or another) claim, it is a good thing to build them almost anywhere.  In practice, though, the nearby once-remote locations soon become filled with sprawl, in no small part because of the initial development, and the theoretical self-contained transportation efficiency never comes.  They become commuter suburbs, just with a more appealing internal design than that of their neighbors."
So can this vision work? Or is building agrarian urbanism like serving a glass of hot cold water? I'd like to play with this a little and consider what it would look like if we followed Duany's vision but flipped it on its head. Instead of embedding hamlets within a rural landscape, the garden block embeds pockets of agriculture within the urban landscape. It is not a stand-alone community but just another gene sequence to be spliced into the DNA of existing inner suburbs and cities.

Start with the standard grid. It can be found all over North America, but the following sketch is based on the 340' by 340' block in the Fan neighborhood of Richmond. Cobble together property ownership for the whole block into something like a community land trust. Households would own their home individually but share ownership of the land with the other 38, in this case, units on the block. Certain commitments to planting and maintaining the garden, either personally or through payment, would be built into an HOA contract.

The exterior of the block functions as in any other urban area. The public streets are activated by the fronts of the buildings and streetscape features, and the full range of transportation access to the rest of the city is available. The interior, on the other hand, is devoted to the more constrained social scale of the block community, and the structures serve as a wall protecting this garden area. Enclosure is necessary to provide a degree of privacy, to protect produce from theft and vandalism, and to keep animals from wandering.

By the numbers, this block allows a density of 15 DUA while keeping 28% of all land for growing produce. This is not food self-sufficiency, but I'm personally not too worried about these kinds of absolutes.

Here are some of the pieces:

Mix of Housing Types. One might expect retirees and young families alike to be attracted to growing their own food, but there is a broad range in housing needs between these two groups. Allowing a range of housing types could facilitate lifecycle diversity, as well as allowing those from different income levels to share the same space. The larger homes include their own growing plot delineated by a short fence.

Shared Resources. The shady northern side of the condo buildings is a place for the utilitarian functions. Gardening requires many resources that can be shared by the whole block. A tool shed is accessed from the side by the glass elevator. A water cistern collects and stores runoff from the buildings above. Chicken coops are lined up against the building. Although chickens need sunlight, some shade could benefit them as well. Maybe they could be on wheels. The composting bins are directly in front of the block's dumpster, so households can deposit their organic waste while taking out the trash.

Childrens' Area -  The playground and "kindergarten" is in full view of the whole grounds. Children have their own 24' by 31' plot to grow whatever they choose. A row of fruit trees creates a sound barrier for the adjacent rowhouses. Being within the enclosed communal area allows parents a certain assurance of safety.

Green Roof. I know these things are expensive for now, but in this case it's integral to the whole concept. Connected directly to the rest of the grounds by an outdoor elevator, it expands the growing area measurably.  Less tangibly, the views to north into the block help create a sense of internal  cohesion, and the southern views to the rest of the city a sense of external connection. 

Greenhouse and Car Sharing. A greenhouse is one of the most efficient uses of solar energy, and it's  necessary in most climates for extending the growing season. A single 4100 sq. ft. greenhouse should be sufficient to meet the needs for the whole block. There is off-street parking available at a rate of roughly one space per three units. The relative paucity of spaces may be compensated for by car-sharing. For areas with greater transit accessibility, this lot could be substituted with two homes.

Corner Store. The corner store is the public interface of the block and a neighborhood shopping hub. Possibly, excess produce and supplies from the garden could be sold here. The upper floors could be leased out to offices or any other reasonably compatible use.

Tuesday, June 22

John Nolen: New Ideals in Planning

I've resumed my practice of reading old (read free) city planning books from the early 20th century to try to mine some insights that may still be useful. Hopefully, this slightly editorialized summary of John Nolen's New Ideals in the Planning of Cities, Towns, and Villages from 1919 may be helpful for anyone who is curious but doesn't have the time to read the whole thing.

Probably more than anyone else, John Nolen was the voice of the early American city planning establishment. He studied under Frederick Law Olmstead Jr. in one of the first graduating classes at Harvard, sat on the board of more professional organizations than you knew existed, and compiled an impressive resume of plans from around the country. New Ideals is both an amalgamation of the basic planning platform of the time and a passionate plea to carry it into action. What stands out to this reader, at least in contrast to the current climate, is the almost uncontrollable optimism written into every page of the book. Just a taste,

"Almost anything is possible through the cooperative effort of such men as are now permanently pulling together toward definite ends in the civic and commercial organizations of scores of cities that might readily be named."
I haven't heard exuberance like this since the brief period between Obama's election and his inauguration, and especially not from hardened planning and development types. Nolen really did believe he was part of something moving history unequivocally forward. 

The case for thinking before acting

The gist of Nolen's defense of planning can be boiled down to simple financial terms. The requirements imposed upon cities by modernity would need to be met somehow. Either local governments proceed through trial and error, leaving a trail of expensive mistakes in their wake, or they think carefully from the outset and get it right the first time. Nolen was fully aware that it was the local Chambers of Commerce, in the end, that would be making decisions for their communities, and he knew exactly how to speak to them.

But his argument is also founded on two more core values: local collectivism, or the ability for a community to make decisions cooperatively for the common good, and local individuality. Nolen bemoans the growing homogeneity of urban landscapes throughout the country and urged community leaders to search for a distinctive identity, whether in nature or culture, and assert it through design. Today, we may view these values as clashing with his more fiscally conservative sensibilities, but many in the business class of his day were equally motivated by a deep sense of civic responsibility. Even when reaching the loftiest heights of idealism, Nolen seems fully aware of the influential audience he was addressing.

Everything is connected to everything

Nolen was what we might call a systems thinker. Here he is on transportation,
"The component parts of a problem cannot properly be separated ... Whenever possible, the entire problem should be considered and attacked as a unit, and the development of the system as a whole should entail the consideration of all transportation routes."
and on parks,
"Just as a city needs a street system, a school system, a water system, a drainage system, and systems to provide for its other municipal activities, so it needs a comprehensive, well-distributed, well-developed system of parks and pleasure grounds."
His goal is to position the newly-formed Planning Commissions as the experts who could see through these moving parts to the "organic whole" and pull it all together. Although staff would aid in data collection and writing, the commissioners themselves are not professionals (compensation is optional, he says) but citizen-activists. They ought to represent the full spectrum of community members - even laborers and women. Although Nolen's writing is a far cry from the full participation that has been strived for since the 1960's, there is a certain sense of real democracy interspersed with some of the admittedly heavy-handed prescriptions.

The primacy of streets

Nolen understood that the street design is the main physical framework of a city. Once they have been laid out, development arrives, and they are very difficult to change. Future widenings for the sake of circulation should be avoided as much as possible, and the widths should vary according to their hierarchical function. He still holds on to the old notion that wider is always better. He simply thinks over-building local roads is too expensive. He then indulges in the perennial planners' debate between the boring, systematic grid-iron and the interesting, albeit somewhat confusing, radial pattern of streets.
"From the point of view of traffic facilities, as well as city attractiveness, the radial system has proved the better one in use"
But in the end, he settles for a hybrid of the rectilinear pattern with radial avenues emanating outward - presumably, once again, to save costs.

Nolen has the habit of treating every individual topic as if it's the single most important topic of all, neatly combining his overall giddiness with his comprehensive attitude toward planning. So street railways are "the chief agencies in promoting progress in cities." Parks are "the most necessary and valuable antidote to artificiality, confusion, and feverishness of life in cities." Zoning is "as far-reaching and important as each of the others, but it is singular in this point, that it costs the city nothing to put it into execution." If you're a mover and shaker in post-Great War society, no matter what interests you have Nolen is squarely (and sincerely, I believe) on your side. This new city planning may be a science, but it's also a coalition.

Learning from Europe while being America

For most of the book, he cites example after example of the British and the Germans getting things right. Forced to rebuild after their various wars, the Germans "achieved success in the replanning of towns for modern life." The English Housing and Town Planning Act of 1909 gets a special mention as a model policy to be imported across the Atlantic.

Meanwhile, American cities were stirring up trouble. New York City decimated their natural features and topography with a rote grid, and everyone else followed suit. Land subdivision was carried out on a strictly proprietary basis, and individual landowners would suddenly find themselves abutting a mismatched street configuration on the neighboring site. Lack of foresight for future public facilities required the destruction of existing structures and payment of higher land values when the need was eventually determined. Cities in America have "but limited powers as compared with cities of Europe." He even insinuates that the poor condition of many neighborhoods may start draining its residents of their patriotism.

Just as all of this starts to feel a little nagging, he turns things around at the end and appeals to a uniquely American art of planning,
"The promise for the future is bright in this field of city improvement in the United States, because we realize that change in our cities, if they are to be permanent and far-reaching, must spring from the people and be at bottom and expression of the life of the people. We do not want mere experts' cities unless those various experts - engineers, city planners, landscape architects and architects - show themselves capable of expressing and interpreting the best impulses and highest ambitions of business men, of citizens, of wage earners, and of fathers and mothers and children."
"When we are stirred in this matter, we shall not be content with a bright promise of cities, nor with visions, dreams, nor even paper plans. We shall insist upon the adoption of methods that will bring definite and satisfying results."
Mixing the art and science of city improvement with American democracy, empiricism, and tough pragmatism is a winning combination, as far as Nolen is concerned.

Monday, June 14

Learning from the early family-friendly suburbs

I ended the last post alluding to ways to make the built environment appeal to young families. Now I'll pull from some of my father's experiences growing up in Ridgewood, New Jersey to illustrate features of what I would consider a family-friendly suburb. Today, these kinds of places are so rare most younger families are completely priced out of them (and many were priced out then too), but the fact that they have existed in the past means they are technically possible to build.

The downtown of Ridgewood, near the New Jersey Transit station. Flickr Credit: Here in Van Nuys

Of the 600 students that my father attended elementary school with in Ridgewood, he recalls roughly 90% of them walking or biking to school every day. If you lived within a mile of the school, this is what you did. You also went home for lunch. The remaining students were mostly residents of a new subdivision built in the mid-1950's. These homes were so isolated from the rest of town, the school district had no choice but to use buses to bring them in. Of course, the rest is history. By the time my generation rolled around, walking to school in the suburbs was a rarity and we all bused. These days, mom drives the kids in and accompanying a child to school on foot is a good way to get yourself fined in some school districts.

The walk to school stats are a good litmus test for a family-friendly community. It has to be fairly compact to yield over 500 kids within a mile radius. The streets have to be well connected to allow a safe route away from the main auto thoroughfares. There's probably sidewalks everywhere, which is the case in Ridgewood. Growing up, my father remembers stopping by a neighborhood convenience store on the way home from school. Another neighborhood store next door gave out licorice in exchange for empty soda bottles. Uses were mixed somewhat.

My father doesn't remember any neighborhood parks, but the limits of the town were within easy reach for him. A wide swathe of undeveloped land and a creek separated his town from Paramus to the east, creating a distinct boundary and sense of territory, at least for a 10-year old. An abandoned trolley track had been used as a de facto walking and biking trail through the town, which made it easier to get around. As long as he was in by dusk, there were a wide range of places to explore.

The center of Ridgewood organically formed around the transit station to New York City, and not much of the development my father knew of as Ridgewood lied more than a mile from it. This is where he went for church, grocery shopping, clothing shopping, the library, the pool, and the weekly YMCA classes. Even the transit station had only a small parking lot attached to it, preserving the valuable central space for use by humans to do all of the things humans like to do.

Is the Ridgewood my father remembers a suburb? Yes, it's a suburb of New York City. But in contemporary planner-speak, it's also a transit-oriented development surrounded by walkable neighborhoods. It really is a town in it's own right. In many of the respects mentioned here, this living environment is as far removed from the late-20th century suburbia as it is from the dense Manhattan its connected to. Most families will probably not choose to live in high-rise condos anytime soon, but if there were places like Ridgewood more widely available, I can imagine many making this choice.

Thursday, June 10

Do young families prefer suburbs?

A couple has a kid, moves out of their condo in the city, buys a house with a big yard, sets up a swing set in said yard, loads up the minivan SUV with backpacks and shin guards, and never looks back. This is probably our dominant life-cycle narrative in America, but does the actual data of housing preferences bear this out. Is this what we want?

There's generally two ways to figure out what people want: see what they do and see what they say they want. Both are tricky.

A new report from Statistics Canada saw what young families did. Between 2001 and 2006, many of them moved out of the Canadian cities of Toronto, Montreal, and Vancouver into the surrounding suburbs. A full 27% of first-time parents made the move out the city and very few moved in. While this is definitely statistically significant, we can't jump to the conclusion right away that these families have a preference for suburbs. As family researcher Clarence Lockhead explains,

I think a lot of what we’re seeing in these patterns are really associated with housing costs and availability of affordable homes. I think that’s a really big factor.”
This is supported by the fact that young families with incomes over $100,000 do tend to live closer in, perhaps because they can afford to be homeowners in high-amenity, walkable neighborhoods. Any market choice reflects both supply and demand. It may look like families are demanding homes in the far-flung suburbs, but it could also be that there is a supply shortage of affordable, urban or inner suburban homes suitable for families. Or a little of both.

Another study just published in JAPA saw what families say they want. Researchers evaluated housing preference surveys conducted throughout the Southwest. They asked questions about trade-offs. Short commute or spacious yard? A Mixed-use neighborhood with things to walk to or a purely residential street? One finding:
"The presence of children in the respondent’s household is linked to less interest in small houses with short commutes, less interest in walkable mixed-use neighborhoods, and less interest in transit-oriented neighborhoods."
The correlation between families and conventional suburban homes was not huge, and it didn't apply at all in some states, but it still does raise our question again. It looks like families are more likely to say they want to live further apart from others, whether they are currently able to do so or not.

Yet here there are complications too. Although the survey tried to force trade-offs, it's impossible to fully construct the multiplicity of real life with questions simple enough be answered in a few seconds. For instance,
"Among the Southwest respondents who embraced a small house and short commute, 39% nevertheless said they preferred to live in a strictly residential (rather than mixed-use) neighborhood, and fully 61% of them said they preferred a low-density, auto-dependent neighborhood."
The researchers note that this is probably not a realistic bundle of preferences, but they were unable to truly force the decision between these ideals.

There's also the difficulty of parsing necessity from contingency. What factors are inherent to a type of physical form and what factors happen to be associated with it in Post-WWII America?  For instance, good schools may come to mind when the respondents imagine a low-density scenario, but there's nothing about the density itself that has anything to do with educational quality. It's just how things happen to have shaken out in recent U.S. history.  On the other hand, a large yard really is logically connected to lower densities, and lots of walkable destinations are only possible in higher densities. If what we're interested in is just the physical form, it's not easy to pull apart the conscious or subconscious prejudices that have become attached to that form in our culture.

I've hopefully been successful in shrouding this whole issue in a cloud of confusion. Or I could just admit that young families might be more likely to want lower densities, single uses, less connected streets, etc. and point to David Alpert's nice post about incorporating shared play space for children into neighborhoods. There's certainly more that can be done design-wise to make urban neighborhoods attractive to families.

Monday, June 7

We now know more about the built environment and transportation

According to Reid Ewing and Robert Cervero, the most intensely researched topic in urban planning is "the potential to moderate travel demand by changing the built environment." Just within the last decade there have been dozens of published studies asking this question from many different angles, using different methodologies. So this dynamic academic duo has decided to do the rest of us a favor and consolidate these studies, pull out a common thread of measurement between them, and weigh the variables against each other. They did something like this in 2001 when there were 14 studies to look at. Now they've compiled results from more than 200 and included about 50 of these in their meta-analysis. I think it's fair to say this is the closest we've yet been to answering this complex question.

The study is published in the Summer 2010 Journal of the American Planning Association, and there are already a couple of nice discussions on the internet from Laurence Aurbach and Kaid Benfield. I have to say that one of the things I appreciate about the planning field is the real interaction between the academic world and practitioners. Working professionals and activists really do read this stuff, and most of the journals make every effort to eschew jargon and ask questions that have relevance.

Here are the land use variables that are traditionally considered in relation to travel behavior:

The D Variables
Summary Description
Concentration of a variable of interest (population, dwelling units, activity centers etc.) per unit of area
Number of different land uses in a given area.
Quantifiable characteristics of the street network, such as density of intersections, connectivity, or streetscape features.
Destination Accessibility
Measures the ease of access to common trip destinations, usually in terms of distance
Distance to Transit
Shortest route along the street network to nearest train station or bus stop

The impact that each of these variables has on travel behavior, whether it's vehicle miles traveled or mode choice, is referred to as elasticity. It's "the percent change in the outcome variable [like vehicle miles traveled] when a specified independent variable [like density of dwelling units] increases by 1%."

There are two more D's mentioned that have little to do with the built environment. They are Demand Management and Demographics. Demand Management is mostly parking supply and pricing, but I imagine any economic factor could be considered under this category. Economic triggers factors can be considerable, especially if fuel prices are taken into account, but I understand how this is beyond the scope of what they are doing. Demographics are contolled for in all of the studies in the meta-analysis.

The following chart presents the findings in ranked order from the most significant factor to the least in achieving three outcomes. The variables are color-coded according to the categories defined above.

Reduction in VMT
Increase in Walking
Increase in Transit Use
Distance to downtown
Intersection/street density
Distance to nearest transit
Job accessibility by auto
Distance to nearest store
% 4-way intersections
Intersection/street density
Jobs-housing balance
Intersection/street density
% 4-way Intersections
Land use mix
Land use mix
Land use mix
Job within one mile
Household/population density
Job accessibility by transit
Distance to nearest transit
Job density
Distance to nearest transit
Commercial floor to area ratio
Household/population density
Household/population density
Jobs-housing balance
Job density
Job density (no effect)
% 4-way Intersections (negative)

Some additional points ...
  •  None of these variables are gamechangers, so don't be a physical determinist. Even the most significant factor, the effect of street density on walking, has .39 elasticity. This means a 10% increase in connectivity would lead to a 3.9% greater probability that someone will choose to walk. That being said, these figures are cumulative, so adding the effects together can make a notable difference. There are no solutions to anything, only means for incremental improvement.
  • The findings seem to show that density itself is not as important as some make it out to be. As they put it, "almost any development in a central location is likely to generate less automobile travel than the best-designed, compact, mixed-use development in a remote location." Absolutely. Although I understand how, in the absence of coherent regional planning, an architect would want to do the best she can with the site she's given. Who knows, maybe in the future it will be the next "central location"? Still, even if it takes cleaning up a brownfield site or working delicately with the neighbors, infill seems to always be more effective.
  • One of the limitations of elasticity is that it measures relative change only. You could be on the verge of a tipping point, and a tiny little nudge would lead to big outcomes, but these numbers would not tell you that. Can those tipping points be identified empirically and built into the same model?
  • A big win for connectivity, which is great because this is something that can actually be done. Some cities and states are starting to write codes to ensure a robust street network in new developments. Even more important is retrofitting connections into existing networks. Hopefully these results will spur localities to look for those odd scraps of land and consider punching a street or multi-use trail through them. Although cycling was not considered in this analysis, I can attest from personal experience that street connectivity is the single most important factor for enhancing safety and convenience. Cyclists would much rather take an alternative back route than ride along a busy road with bike lanes.

Thursday, June 3

More fun with grids

Just ... can't ... stop ... measuring ... grids. Here's some stats on the wide distribution of grid shapes and sizes pulled from around the U.S. (although weighed more heavily toward the Mid-West and West where uniformly gridded cities are more common).