Creating the National Zoning Atlas

Creating the National Zoning Atlas

Massachusetts' new transit-oriented development law requires communities served by the state's public transit authority to create zoning districts that allow by-right permitting of multifamily construction. The state's zoning atlas is expected to help track communities' progress and compliance.

Scholars estimate that approximately 30,000 zoning districts are spread across the United States. The decentralized and complex nature of zoning means that anyone with a stake in land use decisions — including developers, academics, advocates, and the public — may struggle to understand and respond to existing codes. On April 1, 2023, at a session of the National Planning Conference in Philadelphia, panelists described efforts to create a National Zoning Atlas that already is beginning to centralize and organize every zoning code in the nation. The purpose of the atlas is to offer insight into zoning’s effects and democratize land use decisionmaking through comprehensive, digitized, and user-friendly zoning information.

The effort to create the national atlas, which Cornell professor and session moderator Sara Bronin is leading, entails a state-by-state effort that is, as of the conference, underway or completed in 21 states. When complete, each state atlas will encode into a single geographic information system (GIS) database the regulations of each zoning district in that state. According to Bronin’s research, the national atlas will allow researchers an unprecedented view into the nationwide scope and effect of local land use policies. Three panelists represented their state’s atlas projects, including John Infranca, professor of law at Suffolk University Law School who directs the Massachusetts zoning atlas; Max Latona, director of the New Hampshire zoning atlas; and Yoshi Bird, interim director of the Vermont zoning atlas. In each participating state, a cross-disciplinary and cross-institutional team consisting of universities, advocacy groups, and state and regional planning agencies works together to create their state’s atlas, Bronin said.

Building State Atlases From Start to Finish

Vermont is in the early stages of creating its zoning atlas. At this point, said Bird, some of the most important work involves building relationships that will ensure that all stakeholders are heard. This input will shape the state’s atlas to ensure its usefulness to Vermont stakeholders, and coordination with the National Zoning Atlas ensures a degree of uniformity among participating states. Bird anticipates that the Vermont atlas will help advance longstanding but inadequate efforts at zoning code reform. Zoning changes are needed, said Bird, because outdated land use regulations contribute to the state’s housing affordability challenges. An ongoing challenge that the atlas can help address is the obfuscating effects of complex and competing land use interests to reform. In Vermont, the state’s 11 regional planning commissions helped coordinate town and city involvement while university student volunteers helped complete the laborious work of encoding regulations into the atlas database.

In Massachusetts, work on the state atlas is a bit further along than in Vermont, with law students (whose work is supported with a grant from the Mercatus Center) mining the state’s zoning codes covering more than 4,800 zoning districts and more than 40,000 pages of text, reported Infranca. A zoning editor tool is helping to ensure accuracy and speed up the encoding process, while teams of students ensure that raw zoning regulations are being interpreted in consistent ways. The Metropolitan Area Planning Council has partnered with the atlas effort to translate the coded zoning data into GIS. The team is currently working on all Massachusetts cities and towns outside Boston, with plans to launch the atlas in the fall of 2023 before completing Boston, which alone has approximately 4,000 pages of zoning regulations and 450 zoning districts representing about one-tenth of the total zoning districts in the state. Infranca gave one use case example illustrating how he expects the atlas to immediately add value to Massachusetts: the state’s new transit-oriented development law, which requires communities served by the state’s public transit authority to create zoning districts that allow by-right permitting of multifamily construction. The atlas will help measure communities’ progress toward compliance and allow side-by-side comparisons of different communities’ approaches to meeting the requirements of the new law.

Latona reported that New Hampshire has nearly completed its state zoning atlas, which it decided to create in December 2021. The atlas already is helping policymakers clarify the prospects for building needed new housing in the state under existing land use regulations. For example, only 16 percent of New Hampshire's buildable land consists of small lots that can accommodate small starter homes. Building multifamily units near the state's most economically productive areas likewise is stymied by large lot size requirements, which increase the cost to develop multifamily housing and exacerbates the state's workforce shortage and persistently high housing costs. Finally, the map has revealed that, even though homeowners can build accessory dwelling units on their property in much of the state, local regulatory barriers have made doing so difficult for many.

As the panelists demonstrated, the decentralization of zoning laws has hindered the identification of problems arising from land use regulations. Aggregating this information makes the scale of statewide challenges more readily apparent and could bring stakeholders on board to address the collective action problems that intricate zoning systems pose. As progress on the national atlas continues, the cumulative effects of tens of thousands of zoning code decisions will become more easily discernible for researchers, policymakers, and advocates, potentially leading to better housing and land use solutions.