A Placemaking Journal

Codes Study: Trends in zoning reform

About twelve years ago, I started the Codes Study to analyze cities, towns, and counties taking proactive steps toward zoning to encourage livable places. And by livable, I mean mixed-use, economically vibrant, convivial, walkable, bikeable, and transit-friendly. Many places are using form-based codes to encourage livability, in jurisdictions covering over 45 million people worldwide.

Such code responds to today’s market pressures of families and corporations alike wanting to dwell in walkable urban places. It saves critical infrastructure dollars because of building in more compact forms. It can let us preserve more wilderness and productive farm and range lands with less sprawling development. It encourages wellness by making it easier to connect with others, instead of isolating us in single-use pods. It reinjects nature into cities in keeping with the character of its surroundings.

Ten years ago, Dr. Emily Talen joined me as co-author of the Codes Study, unleashing her urban design students to help drill down into some of the particulars of form-based codes: zoning that focuses first on the form of the built environment, and then on the uses within the buildings. These codes tend to build places similar to the form of old cities, where people walk to many — if not most — of their daily needs, instead of the newer suburban development patterns of the last 75 years. The study looks at the scale of the codes: the neighborhood, city, region, state, or nation. We try to cover the population and acreage of the code, when that information is available, along with links to the codes themselves. Matt Lambert has joined us as a third author more recently, and is likely to take us to another level of technology sometime soon.


Initially, we started the Codes Study to create political will within regions: an informal support group of civic leaders, as they remove barriers to balanced budgets, wellness, and environmental resilience. And as you can see from the chart above, regional concentrations have taken off, particularly in areas more challenged by the expense of the dispersed city. Today’s update shows form-based codes that comply with FBCI criteria total 387 adopted codes covering a population of 38 million people. Including the codes that are in process, there are 654 total codes, covering a population of 45 million people worldwide.

Over time, the study has evolved into a look at best practices and lessons learned. For this round of updates, we’ve noticed several key trends: lean codes, unified codes, codes with no parking requirements, and codes that create cash cows.

Lean Codes

Early on in the 36-year history of form-based codes, the initiative rewrote onerous zoning, subdivision, and engineering regulations that were hundreds of pages long and often in conflict with each other. Form-based codes are generally simplified, coherent one or two hundred page graphic, user-friendly documents. These days, the movement has become even more nimble. While it doesn’t remove the weighty underlying zoning, my favorite lean code overlay is the 11-page Cleveland, Ohio Urban Form Overlay District, written by City Planning and Department of Community Development staff.

The Lean Code Tool is an important method of looking at zoning interventions in a small – medium – large – extra large format, with everything from simple text amendments of existing use-based codes to full rewrites. More discussion of the tool is here, or get a PDF or print here. The tool is written by Susan Henderson and Matt Lambert, with Bill Spikowski, and funded by the Center for Applied Transect Studies and the Knight Foundation, via the Lean Urbanism movement.


CNU’s Project for Code Reform leverages this idea to ask how simple, inexpensive zoning interventions can nurture walkability, which may or may not be a full-on form-based code. If those ideas appeal to you, consider joining us at CNU 25 for a day-long Project for Code Reform Workshop, Wednesday, May 3, in Seattle. If you can’t join in person, follow the Twitter hashtag #CNU25 to hit the high points.

Form-Based and Use-Based Unified

We are seeing more unified land development ordinances that combine form-based code governing walkable neighborhoods with use-based code covering the more car-centric areas. Some call these hybrid codes, or more simply, unified development codes. This still deals with making a shorter, more user-friendly document, but also simplifies administrative burdens and becomes a call for investment thanks to clear rules. Thompson’s Station, Tennessee is an example, although with full disclosure that PlaceMakers is the author. Also, Opticos’ Beaufort County, South Carolina is another inspiring example.

Form-based codes regulate urban form, not architectural style. Image credit: Las Cruces, NM.

Form-based codes regulate urban form, not architectural style. Image credit: Las Cruces, NM.

Get Out of the Parking Business

We are seeing more cities getting out of the parking business. Instead of requiring by law a certain minimum number of parking spots per home or business, these cities understand that lenders will not support less spaces than are required for business success. While these cities are still engaging in parking management to specify acceptable parking locations, particularly for the A-Grid, minimums are no longer codified. A good example of this is Buffalo Green Code, led by Camiros.

Coding for Cash Cows

The first city to see over a billion dollars of new development under its form-based codes is Nashville, Tennessee. Long before the first FBC was adopted there, the visionary planning director, Rick Bernhardt, changed setbacks to build-to ranges for the more walkable parts of the city, and required parking be on-street or behind the building. With little more than a two-sentence text amendment in their use-based code, the development community got comfortable with building urbanism.

If I can control just one thing – how the building meets the street – I can deliver livable urbanism.” ~Andrés Duany

Now, the certainty provided by the form-based code is driving value. Nashville’s neighborhoods regulated by “form-based zoning increased 113% in value from 2005 to 2013 compared with 33% countywide.”

Other Cool Innovations

Every time we update the Code Study, I’m inspired by my fellow coders. Here are a few more notable codes, although you’d need to give a look at the 654 codes currently on the study to really do them justice.

Codes based on the idea of the rural-to-urban spectrum of the transect make up 52% of the form-based codes adopted or in process today. They may not use the word transect nor the general terms, but the majority use the idea of these rural-to-urban character zones.

Transect zones are character zones. Image credit: DPZ.

Transect zones are character zones. Image credit: DPZ.

There are a couple definitions of common language, one being in the way that the transect establishes a common language to coordinate planning, urban design, engineering, affordability, and preservation. The second is about moving away from legalese of land use written by and for lawyers, and instead written in plain language of landowners, builders, and designers. DPZ’s Walkable Urban Code for Phoenix removes much of the legalese as well as using the transect as an operating system.

Dover Kohl’s Boulder, Colorado code has some interesting paseos regulations on this frontage code. Check out code section 9-2-16 and Appendix M.

Code Studio’s building configuration illustrations for Fort Worth, Texas are worth a look.

The Michigan Municipal League’s Traverse City, MI FBC has nice flow charts on i.2; how-to on i.3; departures charts on 2.2; and context on 5.3. Consultants assisting the MML were Nederveld and Williams & Works. More good flow charts from Dana Point, California’s Doheny Village, from ROMA Design Group and Opticos.

Additions Always Welcome

The Codes Study,, is a collaborative effort of thousands of planners and coders. If you’ve contributed, thanks again. If you have updates or additions, please let us know and we’ll include in the next update. Until then, keep up the great work!

Hazel Borys

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