Urban Design Discussion

Excerpts from:  Finding Density

Density is central urban strength and diversity, but that is not what makes it pleasurable. Density fosters access but “ease” makes it fun and enjoyable.  Throughout the nation’s major cities, objective “urban area” measures are encouraging designers to create dense places, and they have alot to learn.  The elements needed to describe or judge a dense place are unique to the communities that create them.   Hong Kong is very different from Manhattan.  The commonalities found by original observers such as Kevin Lynch or the “Norman Foster Firms” of the world offer a means for comparison and experimentation but the jargon has proved impotent outside of the designer’s realm.  Something else is needed.  What are the things that make density intense?

Jobs and population per acre are common measures of density, while design components such as the ratio of building mass to open space or height to width helps to frame the quality of the space as an aesthetic experience.  Places from low- to high-density qualify equally and but each is tied to individual place finding or marking abilities that show “position” and in many ways reflect a unique value in the community culture.  And, as sure as polished marble is distinct from graffiti, the use of material and texture in the space completes the experience.

The images in the “patchwork nation” illustrate the U.S. by state or county using 12 “community types” drawn out of demographic, political and socioeconomic data.  Beneath the county layers used here, lie census tract or block groups and any major urban center will easily replicate the patchwork nation image by county.  That the nation has these social “densities” as similarly as a city is encouraging.  It hints at the fractal “as is above, as is below” structure of the urban form.  Another image is produced by dataplace offers a similar view of a zipcode in relationship to the earth with ease.  These too are textures illustrating a pattern over the surface of the earth as if it were a textile.

Density has an odd relationship to land use.  Zoning tends to see a house as always being “a house” or an office complex always limited to business uses, but in an intensely used urban environment, these initial functions yield many new, often unexpected uses regardless of the form.   Density provides the opportunity as a critical mass of human interaction that is often chaotic, but it works best when combined with an open-ended set of form elements that are adaptively re-useable.   This development potential is a form of “intensity” or confidence about dynamically changing sets of land uses.

A region with 100 jobs and 200 residents per acre may illustrate a comparatively dense area in the region and signify a transit-oriented mixed-use center.  Using this measure, furthering the development intensity tier includes the number of time intervals that link to other transit-oriented centers.  These areas might have lower residential/job densities jobs per acre or they may be higher.  Each is identified by an edge where the “intensity” accelerates or declines.  It is the “edge” that is important to maintain.  Density itself only remains significant as an intensifying agent.  It requires edge constraints such as a traditional street grid, or height and scale ratios.   Areas operating without this constraint tend to yield the emergence grey zones, lost landscapes and elapsed trends.   Growth without constraint is what makes and then kills them.  The death is rapid and the residential community behind them are shamed and saddened like the shrinking cities of the industrial mid-west..

Form-Based Growth

Before heading off to University of Utah,  Arthur “Chris” Nelson, was in the Urban Affairs and Planning program at Virginia Tech’s Washington-Alexandria Center.  His research indicated a doubling of the entire built environment in the Greater Washington, D.C. region that could occur by 2030.  The concept of exponential growth is intoxicating in mega regions such as the northeast, but the rate of Greenfield development is by all accounts unsustainable, and that policy measures to focus (if not force) this energy into the existing built environment requires implementation.  Nelson points out most of it could occur by simply using the land represented by the existing parking lots.

Without new restraints, however, the majority of the job growth will occur outside of the urban core areas, resulting in nothing more than a vast enlargement of the current “inner city” building process over much larger section of the metropolitan region.  Conclusions from this analysis demand a form-based regime of land use and building controls authored on a regional basis and of necessity across state lines.  One mega-region is contained with the Florida whose development concerns turned to a form basis.

The purpose of a “form-based code” is to yield to human creative purposes with a greater trust in performance measures and regulations affecting access to natural light, clean air, lack of noise, and other events or qualities that affect the quality of life.  When  Miami 21 was passed in October 2009, the introduction of the “transect” idea may change everything in land use management.  (also see this post)  It is a boundary line around a land area for ecological measurements.  Injecting this idea in to land use and development decisions is not only protective of life, it contributes to the development contextual development events and conversion.  Although the “code” was involved the transition of the West Side Highway in Manhattan into a street near waterfront parkland speaks to this purpose.   Today it is not exactly the Camps-Elysee, but there are aspirations and this potential is now far greater than that offered by former existence as a limited access, elevated super-highway.

The principles of form-based code limit building heights based on the street grids.  Yet as a constraint it recognizes and supports traditional neighborhood resilience.  These communities offer a vibrant series of mixed-use centers that accommodate growth and increased urban intensity.   With multiple forms of public mass transit this intensity contributes to the growth of other mixed-use urban centers throughout the region

The UDC is interested in comments from Raleigh, Cabarrus County, Charlotte and Denver

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