In Print: The Rules That Shape Urban Form

Little doubt exists that zoning regulations in the United States have had an enormous impact on the growth, development, and physical form of American cities. There is also little quarrel among professional planners and sophisticated development interests that the innovation movement of the past few decades, commonly referred to as “form-based zoning,” has been a powerful force for change. The conventional Euclidean approach dates back almost a century and is fundamentally grounded in the separation of land uses and building types. By contrast, form-based zoning has resurrected the lost values of the urban streetscapes, architectural scale, compact development, and mixed uses.

The Rules That Shape Urban Form, a report on the tedious but highly relevant topic of zoning trends, is primarily the product of lead author Donald Elliott, a nationally recognized planner and attorney. Elliott’s previous publications include two highly readable books, A Better Way to Zone and The Citizen’s Guide to Planning.

The thrust of this concise report is twofold and considerably more specific than the title implies. It analyzes six recently enacted form-based codes (FBCs) to demonstrate their varying levels of sophistication in both concept and implementation. However, given such a small sample, the judicious perspective of the authors, and the impact of the most recent recession, only tentative conclusions are reached.

With the exception of Miami, none of the examples has actually replaced existing citywide Euclidean coding. The other five applications are in Austin, Texas; Mooresville, North Carolina; Denver, Colorado; Arlington County, Virginia; and Livermore, California. For each, a short history of community dynamics, often fraught with controversy, traces the period leading up to code adoption and provides a similar accounting of how the code or ordinance has been implemented.

In Austin, for example, rather than rewrite the existing code, city staff designed a freestanding ordinance that was adopted in 2006. This option had the practical advantage of avoiding a rewrite of a complicated existing code while allowing for a more user-friendly document. Officials wanted a new ordinance to tailor required site and building design to the context of different roadway types, ranging from core transit corridors to suburban roadways. The ordinance includes mandatory standards to make sure that building frontages and sidewalks reinforce the streets as a public realm. On-street parking in some cases is counted toward minimum off-street requirements.

On a much smaller scale, Mooresville, with a population of 35,000, passed a zoning ordinance in 2008 with the objective of ensuring architectural unity for most types of development, including single-family residential. From a design standpoint, the ordinance has most of the bells and whistles of a model FBC, while at the same time it includes the Euclidean reliance on buildings categorized by their use. Mooresville typifies the merging of form-based and Euclidean models—what Elliot calls a “hybrid code.”

Miami stands out as the only major U.S. city to discard the conventional Euclidean code and substitute a set of regulations derived from the “transect” or “smart code” model. The process leading to the passage of the Miami 21 form-based zoning code in October 2009 was elaborate, exhaustive, and highly contentious, lasting four years and involving more than 500 public meetings.

The Rules That Shape Urban Form also analyzes the extent to which FBCs are addressing a much larger set of planning considerations—historic preservation, housing affordability, aging populations, and carbon emissions and climate change. The results in these six cities are mixed. FBCs in some cases appear to have no clear advantage over conventional zoning. Say Elliott and his team, “[We] are still only beginning to develop a range of new tools designed specifically to control urban form, especially when high-quality, walkable urbanism is the goal.”

To the authors’ credit, great effort appears to have been directed toward making The Rules That Shape Urban Form accessible to an audience not well versed in code procedures and process. Nevertheless, the inherent complexity of the subject matter presents an almost insurmountable barrier to anyone lacking grounding in code work. But for those who are knowledgeable, especially if they harbor hopes for more constructive reforms in the future, this report is a valuable and timely publication.

Martin Zimmerman writes for Urban Land on transportation mobility, development, and smart growth from Charlotte, North Carolina.