National Zoning Atlas Founder Sara Bronin is Empowering Communities to Transform Land Use

Sara C. Bronin: That’s the primary mission of the Atlas, to make zoning legible to people even who don’t have a technical expertise in zoning, or may not even initially understand the power that zoning has on our communities. We hope that the National Zoning Atlas becomes a tool to help people break through the jargon, simplifying it down to the key elements, which really we think are the outcomes of the zoning. We hope that our tool can be used by planners and advocates and others to try to make that connection to the public.

Meghan Stromberg: With more than 30,000 local zoning codes, the United States represents a patchwork of land use regulations that affect transportation systems, the environment, economic and educational opportunity, and even our food supply. They also greatly impact housing availability and have for decades divided communities along socioeconomic and racial lines.

Today, the country is facing a historic housing shortage, which could be alleviated, in part, through zoning reform. But understanding all these zoning codes in the first place is far from easy. Their language is not known for being approachable or accessible to the average citizen, and they vary widely from place to place. But lawyer and Cornell professor Sara C. Bronin is aiming to change that.

Bronin created the National Zoning Atlas, a research collaborative working to digitize, demystify and democratize zoning codes. Its aim is to give everyone, from citizens to elected officials to planners, the information they need to help tackle the housing challenges in their communities. Also a specialist in historic preservation, Bronin has advised the National Trust for Historic Preservation and served on the board of Latinos in Heritage Conservation. Previously, she led the award-winning, unanimously adopted overhaul of the zoning code and city plan for Hartford, Connecticut.

I’m your host, Meghan Stromberg, editor in chief of the American Planning Association. Today, we’ll talk to Sara Bronin about her work on the National Zoning Atlas and ask her how it can be used to help build support for zoning reform. Sara, welcome to People Behind the Plans.

Sara C. Bronin: Thank you so much for having me, Meghan.

Meghan Stromberg: You’re an architect and attorney specializing in historic preservation, equity and sustainability. Can you tell us a little bit more about your background and where your interest in the built environment comes from?

Sara C. Bronin: Well, I grew up in Houston, Texas, which many people say is the largest city in the country without zoning. It does have zoning-like rules, to be clear, but in general, it developed in a way that is sprawling, somewhat incoherent, and in many places not too beautiful. Thinking about growing up in Houston, as I went through architecture school and then law school, really encouraged me to interrogate the way our built environment was made. And when you start unraveling that thread, all layers of inquiry lead right back to zoning and historic preservation rules to some extent. So I think you could really go back to me sitting in the back of a car in Houston, Texas, driving for an hour to get to piano lessons, and for a year there, an hour to get to school. And that probably inspired the very work that I’m doing today.

Meghan Stromberg: So, the National Zoning Atlas was launched in January of 2023, but it has its roots in a state-level initiative in your state called Desegregate Connecticut. And people have called it a groundbreaking development in the movement to democratize data and to use it as a tool to change policy. Can you tell us a little bit about Desegregate Connecticut and how it helped to spark this interest in a national zoning atlas?

Sara C. Bronin: The efforts in Connecticut were really motivated by land use professionals in the state questioning their role in creating entrenched segregation in our state. If you look at Connecticut cities and towns, that income-based and even race- and ethnicity-based segregation is pretty clear. And at the time that Desegregate Connecticut was formed in 2020, we were all wondering whether there was something that could be done about the land use rules that dictate where people can live and how. As we were looking to support the advocacy for that effort, it dawned on us that we didn’t really know how Connecticut communities zoned. We had some ideas because we could see what had been built in those communities. Nobody had really done a survey across the state of all of the different intricacies of zoning codes, and nobody had really enabled an apples-to-apples comparison. We created the methods that are now used in the National Zoning Atlas in Connecticut to address those issues, to be able, for us as people interested in the role of zoning in Connecticut, to make apples-to-apples comparisons. And what that meant for us was standardizing the way that we extracted information from over 180 zoning codes in the state, and then taking that information and displaying it into a map that the public could interact with. The Connecticut Zoning Atlas enabled people to see how zoning worked in their towns, and it also enabled them to use features that calculated the percent of land that was, for example, zoned for single-family housing versus multi-family housing. And that’s exactly what you see in the National Zoning Atlas today.

Meghan Stromberg: I’m sure that opened up a number of conversations in your state. Anything you didn’t expect?

Sara C. Bronin: I think the most surprising statistics were the summary statistics of the way the whole state zoned — specifically that 91% of the state land allowed single-family housing as a right, and just 2% of land allowed three-or-more-family housing as a right. Those statistics were only made possible by the way that we extracted information about individual zoning codes — about 2,600 of them — across the state. And when we got the final calculations in for the state, we realized that those two data points alone painted a very powerful story about how we had made these individual local rules, and in the aggregate, added up to something that was hurting our economy, our environmental sustainability and, of course, equity.

Meghan Stromberg: I know that planners and APA state chapters have been involved in the development of the National Zoning Atlas. I wonder if you could tell us a little bit about the role of planners.

Sara C. Bronin: Planners have played a big role in many of our atlas projects. For one thing, they help provide us with the texts and the maps that we can then analyze using our methods and upload into the Atlas. But they’ve also helped us to check data and information, explain certain things that happen, maybe only in their town, and also connect us to networks of planners. I’ll use Connecticut as an example. The APA chapter there was active in the effort to create the Atlas and to advocate for reforms at the state level. The Michigan chapter of the APA is also active in the Michigan Zoning Atlas. We’ve given presentations to the Florida APA and others, as well as the National Conference of the APA. Our staff, too, is filled with planners. Our zoning code coordinator, Aline Fader, was at the city of New York’s planning office for 11 years, where she oversaw a lot of complicated processes to help simplify and streamline their zoning code applications. In addition, all or almost all of our zoning code analysts have worked in local government as planners. So, I mean, the role of planners and planning is extremely big in the National Zoning Atlas, and we intend to keep it that way.

Meghan Stromberg: Sara, I’m wondering if planners ever come to you saying, “When are you going to do an analysis of my town or of my state?” And it also makes me wonder, how do you choose which places you’re going to research?

Sara C. Bronin: So in part, we do get inquiries from people, and sometimes they come with funding. So I’ll use the Colorado example. There are a group of funders in Colorado led by Housing Colorado and some other foundations that have pooled money and said, “Hey, we want a Colorado atlas. Here’s the funding. Go forth, and do it.” And so we are starting on Colorado this month in partnership with some folks at UC Denver, and we’ll hope to accelerate completion of that state.

We’ve seen that our funding from the federal government, our funding from HUD, the U.S. Department of Housing and Urban Development, is primarily devoted to large metro areas because that’s the type of community that HUD is interested in seeing on the Atlas. At the same time, we’ve tried to think as a team about how we diversify the ways we both support the project, but also look to communities around the country like those planners who do come to us, in fact, asking, “Hey, when’s my town going to get on the Atlas?”

And hopefully in the next couple of weeks, we’ll have rolled out a way for local communities to ask us to do their town. We’ll hopefully have a transparent fee schedule as to how that will be accommodated. And then when we do get those queries, we’ll be able to put somebody on our team on that town, and they’ll be able to see it in the Atlas, when we wouldn’t have otherwise decided to go to that community, in part because of the way that our current funding structure works, which is primarily geography based.

Meghan Stromberg: I wonder if you’ll see a time when communities will see their neighbors being part of the National Zoning Atlas, and they’ll feel like they also need to be a part of it, too.

Sara C. Bronin: Well, we hope that people are interested in seeing their communities up in the Atlas because it will illuminate what’s going on in their towns. We do hope there’s a snowball effect because simply put, there are 36,000-plus local governments across the country. We actually don’t even know how many of them have zoning because we have never done a nationwide survey as to which ones have zoning and which ones don’t. And so far, despite a year-plus of effort, we only have 2,300 jurisdictions up in the Atlas itself. So, we still have a long way to go. And we can build this town by town, or if we can build it state by state, we’re willing to put in the work, pull that tapestry together and try to fill out as much of the country as we can.

Meghan Stromberg: If you think back to just a few years ago, did you have any idea that zoning reform would be part of mainstream conversations? How can the Atlas help to explain zoning issues to non-planners?

Sara C. Bronin: Well, that’s the primary mission of the Atlas, to make zoning legible to people even who don’t have a technical expertise in zoning or may not even initially understand the power that zoning has on our communities. In coordination with planners, we hope that the National Zoning Atlas becomes a tool to help people break through the jargon, prevent them from having to read a 300-page zoning code, or look at a color-coded zoning map and simplifying it down to the key elements, which really we think are the outcomes of the zoning, what the zoning actually permits. We hope that our tool can be used by planners and advocates and others to try to make that connection to the public. We hope that it’s simple enough in concept that it distills these very complicated texts and maps and makes them accessible for people.

Meghan Stromberg: APA believes that reforming zoning is a critical first step to producing more housing. How do you see the Atlas influencing those conversations with planners, policymakers and the public? And how can planners use the state atlases to push for state housing reform?

Sara C. Bronin: I’ll start with the second question first, which is about the statewide projects. So far, we’ve completed atlases in four states: Connecticut, New Hampshire, Rhode Island, and Hawaii. And we just announced that we are embarking on the creation of full state atlases for six additional states: Alaska, Colorado, Georgia, North Carolina, Utah, and Arizona. What we found in creating statewide atlases is that you can use the summaries of the state in ways that are extremely influential on policy.

In Connecticut, when we completed the atlas, we were able to use those summary statistics I just cited to catalyze a series of conversations at the state legislature and ultimately to start the process of updating state zoning laws, including laws on accessory dwelling units and minimum parking requirements.

We also know that the Atlas has been used at the local level by planners, both using just the very basics — the screenshots, what we call the percent-satisfies tool that shows you the percentage of land that is devoted to the filtering criteria that someone sets out in the Atlas. They’ve used those in city planning documents, they’ve used those in regional analyses, and they’ve used the Atlas to inform a variety of both local reforms and policy analyses. And we hope that using the Atlas in a lot of different ways, being able to compare one jurisdiction to another, playing with the filters that are on the website — including the minimum lot size and minimum parking requirement, including the requirement that housing developments must be, for example, connected to transit — these are all intricacies of the zoning code that, when you add them up, contribute to whether a place can build housing or not.

And so we hope that when planners use the tool, as they think about policy analysis and reform, that they are delving into all of the different facets that the tool can be used for and use it to inform their decisions.

Meghan Stromberg: Are there any unexpected uses so far of the tool?

Sara C. Bronin: Well, just last week I was contacted by a national self-storage facility company who was inquiring about whether we were collecting information about self-storage facilities, which we are not. But it suggests that there is at least a desire out there to have more information about the ways that we use land, not just for housing, which is what the current version of the National Zoning Atlas focuses on. We have added a category for the most common residential use in a place. So, for example, a typical downtown might have an array of commercial uses. You might also see housing paired with office, or even in some cases, housing with industrial or light industrial uses. We have found a way to categorize that, but we haven’t broken out individual uses to the level of detail. So in the future we might see some more queries on that. And who knows, you might see a self-storage facility layer in this Atlas at some point.

Meghan Stromberg: Sara, we’ve talked about a couple of different places, a few states who’ve already seen some outcomes from their zoning reform efforts, but one that we haven’t talked about yet is Montana, which has made a lot of movement lately. I wonder if you could tell me a little bit about what’s going on with zoning reform there.

Sara C. Bronin: So they call it the “Montana miracle,” and I know you’ve covered it in Planning Magazine and The New York Times has covered it. The governor of Montana was at YIMBYtown this year — which was a great event, by the way, and very energizing. They call it the Montana miracle because of the suite of zoning reforms that were made at the state level. And the group that led those conversations, the nonpartisan group called the Frontier Institute, played a big role in not only the advocacy side, but also in developing an atlas for the state’s largest cities that inform the debate. And when you hear the CEO of the Frontier Institute, Kendall Cotton, talk about the success in Montana, he does cite the Montana Zoning Atlas and the ability to bring legislators and city leaders the facts about how their communities zone. And the ability to compare one city to the next, he says, has been instrumental in making change and informing the public about what their current zoning is and what the opportunities to change in the future are.

Meghan Stromberg: And Montana, like so many of the states you’ve mentioned, have both big cities and more rural places and small towns, so there must be quite a bit of difference across the landscape in terms of zoning codes in those places.

Sara C. Bronin: Certainly. What you see in the big cities is, as expected, much more complicated codes, longer codes. The longest one, by far, that I’ve seen is the city of Boston, which has about a 3,800-page zoning code.

Meghan Stromberg: Wow.

Sara C. Bronin: For a city of 42 square miles, that’s a little excessive, but we’ve also seen codes that were made in the 1980s that were maybe photocopied and then scanned, or sometimes not even provided online. And I would say that that’s something that we find in more rural areas where they don’t update the zoning code very frequently because they don’t see a need to do that. Oftentimes the older codes are also simpler codes. So you see zoning codes as little as 20 pages. And actually, if you go back to the original New York City zoning code in 1916, it was about that same length. Now we have much more complicated texts. And I think the level of complication, especially in the larger suburbs and of course, the larger cities, is one reason why we feel like this Atlas can help people understand those and create ways for them to access these extremely lengthy documents.

Meghan Stromberg: Well, it must give you so many insights into something that literally we’ve never been able to look at on this scale before. So that must be really, really exciting.

Sara C. Bronin: I have never stopped learning with this project. And you think you’ve seen it all, and then all of a sudden, you’ll see a zoning code with a phrase like “man camp.” We’ve seen zoning codes that have maybe just two uses in them. We’ve seen zoning codes that have really specific terms for accessory dwelling units, not just granny flats and so on, but some more creative ones. This has been a project that’s geared toward the curious, geared just toward people who want to know. And we have about 21 full-time staff members now on our team. I love our team because they’re interested in knowing, and their curiosity, you know, is infectious. And for people who are interested in reading zoning texts and digging into zoning code maps all day, this is an awesome project because over time you get a sense of that scope, and you get a sense of the differences and the uniformity across jurisdictions, but also the creativity and how that uniformity comes about. I think that’s just inherently interesting.

Meghan Stromberg: I’d like to end this conversation by talking a bit about where you see the National Zoning Atlas going. We’ve talked about it as an advocacy tool to show, as you’ve said, decision makers and policy makers what those trends are in their states and communities that they might not even be aware of. But planners also have access to all sorts of data and other resources. Are planners using the Zoning Atlas in combination with other data to drive decisions to inform policies and the like?

Sara C. Bronin: We’re already seeing collaborative research projects on a few different big-picture topics where zoning has played or could play a role. One example of that is what I referred to when I talked about the impetus behind the Connecticut Zoning Atlas, which is the correlations between current zoning and racial and economic and ethnic segregation, household incomes and so on. Another is the relationship between zoning and sea-level rise. So we are working in collaboration with the Regional Plan Association and others to develop an understanding of where in the New York City metro area we are putting housing and correlating that with areas where that housing is likely to flood. So, you know, is this really smart policy at the local level or at the scale of the New York City metro area? I think we’ll find out pretty quickly.

Our geospatial coordinator, Scott Markley, who has a PhD in geography, has been generating ideas for additional future research. And one of those ideas is zoning in urban heat clusters. Another is the relationship between zoning and transportation and carbon emissions. If you have large-lot zoning, our hypothesis is that you’re going to have a community that drives more. You’re going to have a community that emits more carbon. Can we really put the empirical methods behind that hypothesis, test it, and as I think we can all predict, prove that it’s true? So I think zoning has so many different impacts on the way that we live that the possibilities for overlaying our data with other data sets is very, very strong. And I look forward to all of that going forward.

Meghan Stromberg: I do, too. It’ll be really fascinating to see in the next few years the research that comes out of this really important work you and your team have done on the National Zoning Atlas. Well, Sara Bronin, it has been such a pleasure to talk with you on People Behind the Plans. Thanks so much for coming on to the podcast.

Sara C. Bronin: Thank you so much for having me.

Meghan Stromberg: Thanks for listening to another episode of People Behind the Plans, an APA podcast. If you want to hear more great conversations with experts from across the planning landscape, subscribe to APA podcasts, so you’ll never miss an episode. And if you like what you’re hearing, rate us on iTunes. You can find People Behind the Plans on Spotify, Apple Podcasts, Stitcher, or wherever you get your podcasts. You can also find our entire library of episodes at planning.org/podcast.