The city of Ann Arbor has made ambitious commitments to housing affordability and carbon neutrality. Reform of land-use planning to provide for increased housing supplies in areas near work, recreation and entertainment can help with housing affordability by reducing pressure on existing housing stock and with carbon goals by enabling people to drive less. This reform should very much be on the table as the city sets its policy directions.
Housing affordability demands a commitment both to the provision of subsidized housing and the expansion of housing development in the traditional market. While the connection between market-rate housing development and affordability is frequently contested in local political discussions, the research is quite clear: Zoning for low development densities, including exclusive single-family zoning, is a significant impediment to housing affordability. Conversely, reforms that ease those constraints can increase housing supply, moderate the growth of housing prices and offer affordability benefits to households with a range of incomes. This point is often missed because new housing is most frequently developed at the high end, and the units produced would not remotely qualify as affordable. The affordability impacts go beyond newly developed units because of the interconnectedness among different segments of the market. Where the supply of new market-rate housing is constrained, its would-be occupants compete for and drive up the cost of existing, older housing. By contrast, the lifting of those constraints to allow new market-rate housing has been shown to trigger a rapidly operating “migration chain,” which frees up housing throughout much of the income spectrum. In addition, using negotiated agreements and other developer requirements, cities can harness profit-driven, market-rate development to expand subsidies, which are necessary to ensure housing security for the lowest-income households. Greater diversity of population demands a greater diversity of housing stock, and these approaches are steps to overcoming historical inequity and racial disparity in housing.
The goals of enhanced affordability and carbon reduction are interconnected. Ample supplies of close-in housing aid in affordability by lowering the cost of transportation for residents. Transportation is the second-largest item (after housing) in the household budget, accounting for about 16 percent of expenditures. These costs are shaped both by the distance one has to travel and the transportation alternatives one has available. For example, a household in downtown Ann Arbor faces annual transportation costs of $8,319, compared to $11,135 in Ann Arbor as a whole and $14,610 in Ypsilanti Township.
The carbon savings of close-in development are closely related to its transportation cost savings. A household in downtown Ann Arbor drives about 12,000 miles per year, compared to 17,000 for Ann Arbor as a whole and 23,000 for Ypsilanti Township. Close-in locations are, for this reason, relatively low carbon zones. The carbon-reducing effect of these zones, however, depends on the number of households able to locate there. Low-density zoning excludes households from these areas and pushes them into locales that are likely to generate much higher transportation-related carbon emissions. Location matters for job sites as well. A worker in downtown Ann Arbor has about a 27 percent chance of walking, cycling or taking transit to work; that number drops to 3 to 6 percent for workers in Scio, Pittsfield or Ann Arbor Townships.
Some people equate sustainability with avoiding or limiting growth of local housing supplies. Yet, when it comes to carbon reductions nationally, it is carbon impact per resident or per worker that matters. Hence, Ann Arbor’s way to contribute to carbon reduction goals is by reducing emissions per capita. Ample housing supplies near the large job concentration that is Ann Arbor — and jobs in zones that offer good alternatives to driving alone — are important tools to achieve that goal. The commute to Ann Arbor and use of the private car will always be with us, but given the opportunity in the form of increased housing supply, some of the approximately 83,000 daily in-commuters to Ann Arbor (as well as those whose shopping, social or educational destinations are in town) would choose locations that allow them to drive shorter distances, use transit, cycle or even walk.
Fortunately, the reforms that can provide these benefits have been pioneered elsewhere. For example, Minneapolis and Oregon have allowed small multi-family homes in formerly single-family zones without altering height, yard space or other size and design requirements. The San Francisco Bay Area is experimenting with transit-oriented development along rapid bus corridors. Buffalo, Hartford and other locales have eliminated parking requirements from their zoning codes to allow high-value land to prioritize residential, commercial or institutional uses over car storage. Austin has relaxed certain height, density and parking restrictions for development that contains enough affordable units. In many cases, new housing that shares in already-developed infrastructure helps municipalities' bottom line as well. In Ann Arbor, for example, the new construction of the past ten years contributes approximately $10.3 million annually to the city’s General Fund and $16.5 million to all city millages.
With the recent adoption of the A2Zero carbon neutrality plan, Ann Arbor has recognized the relevance of housing to carbon emissions, and residents should insist on its full implementation. While the specific reforms that will be right for the Ann Arbor context remain to be determined, no affordability or carbon policy would be complete without serious consideration of the place of increased housing supplies and the zoning reform that is needed to bring them about.
Lan Deng is an Associate Professor of Urban and Regional Planning at the University of Michigan and can be reached at firstname.lastname@example.org; Robert C. Hampshire is an Associate Professor in the Gerald R. Ford School of Public Policy at the University of Michigan and can be reached at email@example.com; Jonathan Levine is a Professor of Urban and Regional Planning at the University of Michigan and can be reached at firstname.lastname@example.org; Neda Masoud is an Assistant Professor of Civil and Environmental Engineering at the University of Michigan and can be reached at email@example.com; Marc Norman is an Associate Professor of Practice of Urban and Regional Planning at the University of Michigan and is also the president and founder of Ideas and Action, a consulting firm, and can be reached at firstname.lastname@example.org; Anna G. Stefanopoulou is the Energy Institute Director, William Clay Ford Professor of Technology and a Professor of Mechanical Engineering at the University of Michigan and can be reached at email@example.com; Paul Webb is Professor Emeritus in the School of Environment and Sustainability and Professor Emeritus and former Director of the Program in the Environment at the University of Michigan and can be reached at firstname.lastname@example.org.
* Titles are given for identification purposes only and do not indicate university support for or endorsement of the views advocated here.