• Credit: Headcase Design

Nobody ever really reads a zoning code, unless you want to rewrite it. That’s what the city of Miami experienced over the past five years as it replaced its old zoning code with a new one, dubbed Miami 21.

“I’ll tell you one thing: Miami 21, everybody read,” says former Mayor Manny Diaz. “From commas and semicolons to substantive provisions.”

That’s partially because the process of rewriting the code was made intentionally participatory, with more than 500 public meetings throughout the process. But the main reason it was so closely scrutinized is because the new code is a form-based code, one that seeks to achieve a specific urban form by focusing on the relationship between buildings, streets, and public spaces.

“There was resistance up front. And, I wouldn’t kid you, there’s still resistance,” says Diaz, who was termed out of office last fall. Miami 21 is likely the most important legacy of his tenure at the city’s helm. The new code emphasizes mixed uses, walkability, and the predictable development of neighborhoods via “orderly housing transitions” and “proportional buildings with proper setbacks,” among other urban design principles.

While Miami’s form-based code is the best known of its kind, it’s certainly not alone. “We haven’t been able to keep up with the explosion,” says Carol Wyant, executive director of the Form-Based Codes Institute (FBCI). The institute is a group of architects and planners who advocate for this new kind of zoning. Well, it’s not exactly new, but it’s definitely different from what most cities and towns have had in the past. And now, more and more of them are switching things up.

“There are hundreds of codes that have been adopted,” Wyant estimates. A recent study by the consulting group PlaceMakers confirms this: At press time, it found 323 form-based codes either adopted or in development in the U.S. and Canada.

Miami was the first large American city to adopt a form-based code, but Denver was close on its heels, adopting its New Code in late June. Montgomery, Ala., has one. So do Sonoma, Calif., and West Evanston, Ill. But according to Wyant, the most common use of the form-based code is much smaller in scope. “The trend for a long time has been neighborhood by neighborhood, doing a portion of the city, focusing on those types of places where there’s a either a problem of disinvestment, a problem of development pressure, or of losing historic resources,” Wyant says.

For architects, the idea that a code is going to dictate the form of their buildings may seem heavy-handed. But the creator of Miami 21—and of the first ever form-based code—says they’re really not so different from what architects already deal with.

“It’s not unlike architects working with design guidelines,” says Elizabeth Plater-Zyberk, lead consultant for Miami 21. “And it’s not unlike architects working with conventional zoning codes and building codes, in that there’s a kind of intellectual contract within which one tries to produce a great place.”

The conventional method of zoning, known as Euclidean zoning, determines what sort of development can be located in specific areas based on type of use. So houses end up near other houses, factories near other factories. But that division of land uses can make it difficult or even illegal to build developments that mix different but compatible uses, like an apartment building with ground-floor retail. The separation of uses written into Euclidean zoning codes made sense to the lawyers who wrote them, but they have the effect of creating bland and inefficient places, Plater-Zyberk says. As a response, she and other New Urbanists developed an alternative, the form-based code.

Instead of focusing only on the separation of types of land uses, form-based codes are organized around the physical form that a development should take. Under the guidance of a regulating plan, form-based codes emphasize connectivity between buildings, their façades, and the public realm, and how those connections play out across variously scaled streets and blocks.

Great places weren’t being produced under Euclidean zoning, according to Plater-Zyberk. “It became evident that this regulatory framework was really what was driving suburbia, sprawl, and the things that were being criticized as being inefficient and unsustainable,” Plater-Zyberk says. “It wasn’t that people wanted it to be that way—the codes were just written that way.”

Plater-Zyberk, who’s also the dean of architecture at the University of Miami, is a co-founder of the Congress for the New Urbanism and a principal at the influential architecture and planning firm Duany Plater-Zyberk & Co. (DPZ). Her DPZ co-principal, Andrés Duany, also helped found the Congress—and sits on the board of the FBCI. For its part, the FBCI is supported by funding from philanthropist Richard Driehaus, a champion of traditional architecture. In short, form-based codes are deeply rooted in New Urbanism.

“Most zoning codes are written from sort of a legal, attorney’s point of view. So they’ve got a lot of words,” says Peter Park, manager of community planning and development for the city of Denver (and a long-time Congress member). “A lot of times, they’re just telling you what you can’t do.” Park says Denver’s form-based code tries harder to guide developers and designers toward what they can do, mainly by being a very visual document. Drawings of example neighborhoods and streetscapes are on nearly every page in the city’s New Code, which Park says helps give everyone a better idea about what impact the right kind of projects can have.

But having a picture book for a zoning code was a bit worrisome for some of the city’s architects. Paul Brady is an associate principal at Godden|Sudik Architects and the chair of the housing committee of AIA Denver, which helped the city fine-tune its New Code through the writing process. He says that earlier versions of the code had many architects concerned about losing some of their design freedom. “The early drafts were definitely a lot more prescriptive,” says Brady, who cited tight rules on wall lengths and plate heights and what seemed an incredibly limiting guideline on roof pitches. But after collaboration between architects and the city’s planning staff, most of the concerns were ironed out. “What’s being enacted, I think, doesn’t concern anybody,” he says.

And that’s actually one of the main goals of a form-based code. By using a charrette format to gather public input and debate design ideas that define the final code, it’s hoped that projects approved under the community-vetted code will be NIMBY-resistant.

“The code is really a tool to implement the vision that everyone has agreed upon. So it’s more time- and labor-intensive upfront, but once everyone’s agreed on the vision, then the rules are very clear and the process for development goes much more quickly,” claims Wyant. “There don’t have to be public hearings, and the NIMBYs don’t have to show up, because the project conforms with the vision everyone’s agreed upon.”

Visions can change, of course, so most form-based codes are written to be able to evolve along with the changing land-use environment—and to help fix any mistakes made along the way.

The form-based code adopted in 2003 for the Columbia Pike area in Arlington, Va., has seen numerous changes over the years. “There’ve been some ups and downs. We’ve gone back and modified and updated and amended the form-based code to be as exact and as correct as we thought we had been in the beginning,” says Richard Tucker, a planner with the county who helped develop the code. He says the code was much more flexible than a traditional zoning code. “Some of the things we were absolutely descriptive about, we were absolutely wrong about. So we had to change some of those things.”

Miami architect Bernard Zyscovich has been perhaps the most vocal opponent of Miami 21, arguing that it could transform the city into a monotonous spread of look-alike buildings and neighborhoods. “It homogenizes the city’s form,” he says. “Sometimes, the change of form from neighborhood to neighborhood as a result of architectural evolution is something that’s one of the best assets of a place.”

Zyscovich says the formula of Miami 21 doesn’t recognize the difference between neighborhoods such as tree-lined Coral Way and bustling Little Havana. He also doubts the purported guiding vision behind it. “It’s not based on a vision or a master plan—it’s based on making easy regulation,” he argues. “The result for the architect is that he becomes the decorator of the forms that are imposed.”

Plater-Zyberk says she and her team encountered this sort of skepticism as they were pushing Miami 21 forward. And though Zyscovich is still arguing against the code, Plater-Zyberk believes that most protests have faded away. Killing the creative spirit of architects is not the goal of a form-based code, she adds.

“If the architects could understand that they’re part of a larger effort of placemaking, and it’s not just a restriction like any old code, I think that they would have a good time working with form-based codes.”

Houston is the largest American city with no formal zoning code. The freedom that affords might seem exhilarating to architects, but working with no limitations isn’t all it’s cracked up to be, says Carlos Jiménez, principal of Carlos Jiménez Studio in that city. “It’s a perplexing reality that has created an urban and suburban concoction,” he says. “So from that perspective, a form-based code might benefit a city like Houston, by implementing a more cohesive set of guidelines to improve on the public character of the city and, more critically, to foster density.”

“Often ‘design freedom’ becomes another term for ‘anything goes’ solutions that contribute little, if any, to the collective enterprise,” Jiménez adds. “Limits are not the curtailing of freedom, but rather opportunities to transcend them.”