Driving Change Through Parking

Automobile dependence in urban centers poses a barrier to densification, housing affordability, equitable transportation, and reducing greenhouse gases, yet driving is a difficult habit to shift people away from. As a result, some cities are taking a market-driven approach to address the issue from a new lens by removing minimum parking requirements (MPRs).

In the article "Minus Minimums" (Journal of the American Planning Association, Vol. 87, No. 3), Daniel Baldwin Hess and Jeffrey Rehler examine the impacts of removing MPRs on parking and development in Buffalo, New York. Buffalo was an ideal "natural experiment" because the city adopted a new zoning code in 2017 known as the Green Code that eliminated MPRs citywide. In the updated ordinance, officials aimed to shift the city away from cars and toward active transportation and transit-oriented development (TOD).

Parking Reduction in Mixed-use Developments

To conduct their investigation, Hess and Rehler examined 36 developments approved in the first two years after the adoption of the Green Code. They used publicly available transportation demand management (TDM) plans submitted to the city to track the amount of off-street parking approved for developments. They then compared these to 16 developments approved in the five months leading up to the code change, choosing developments that would have required site plan approval under the new code.

From their research, Hess and Rehler uncovered two key findings:

• Parking supply was significantly reduced for mixed-use developments after the code reform.
• Deregulation provided choices for developers about parking provision, though their decisions were not uniform.

For the 36 developments analyzed, there were 21 percent fewer off-street parking spots planned than would have been mandated before the Green Code, but the overall reduction was not statistically significant. When Hess and Rehler specified by land use, however, they found mixed-use developments offered 53 percent less off-street parking than previously required, which was statistically significant, whereas single-use projects were not affected by the removal of MPRs.

Table 1. Distribution of parking supply by land use.

MPRs Removal Boosts Transit Accessibility

The removal of MPRs was most impactful in transit-rich, primary commercial corridors where developers could gain approval for projects like high-density student housing without needing land for off-street parking. This research shows that MPRs have likely restricted mixed-use development in central, transit-accessible, and dense areas.

The study has its limitations given its small sample size and relatively short time frame, so for more conclusive arguments about the impacts of MPRs on parking, development, and automobile dependence, researchers may wish to continue the investigation as a longitudinal study. Additionally, more cities are beginning to adopt similar zoning code reforms, so research should be done in these cities to expand the study's scope.

Nonetheless, Hess and Rehler's findings do have important implications for cities across the US. Cities should take comprehensive approaches to the reduction of car dependence; removing MPRs alone is likely not enough, however, pairing these reforms with other TDM plans can encourage developers to promote other methods of transportation through public transit pass subsidies or bike parking. Ultimately, removing MPRs could play a powerful role in increasing density, reducing air pollution, reducing housing costs, and improving walkability and equitable transportation in our cities.

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