What Is the Rationale for a Minimum Residential Street Width Requirement?

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Part Two of Mineta Transportation Institute’s research recommends money-saving changes.
July 17, 2012
San José, CA

The Mineta Transportation Institute (transweb.sjsu.edu) has released a peer-reviewed research report, Amenity or Necessity? Street Standards as Parking Policy. This research – the second in a two-part series – investigates the rationale behind the parking mandate for a minimum residential street width requirement adopted by most US municipalities. This standard provides between 740 million and 1.5 billion parking spaces on residential streets, costing trillions of dollars in road investments. This research explores the two common beliefs underlying the parking mandate: that it is an amenity reflecting market demand, and that it is a technical necessity based on traffic safety concerns. The principal investigator was Zhan Guo, PhD, in close coordination with Charles Rivasplata, PhD, Richard Lee, PhD, David Keyon, and Luis Schloeter.

“A minimum width requirement of 36 feet for a residential street automatically provides two 10- foot traffic lanes and two 8-foot parking lanes, making it a de facto parking policy,” said Dr. Guo. “The study found that local decision makers have an inconsistent and ambiguous understanding of the rationale for mandating this requirement. They believe that parking is provided because residents and visitors need it, but in reality it is provided through the minimum width requirement under the guise of technical necessity. This inconsistency calls into question both the amenity and necessity arguments.”

In addition, he said, decision makers fail to adequately explain the double standard in parking requirements, in which the minimum width is much narrower for private streets than for public streets. Respondents used the same amenity and necessity arguments to explain the requirement differences, which suggests that the parking mandate is likely neither an amenity nor a necessity.

The report suggests two policy reforms. The first is to surface the “submerged” parking mandate by making it a stand-alone policy, so it no longer hides behind the technical street standards, avoiding public oversight. Street parking should be addressed separately in development regulations with a detailed analysis of residents’ and visitors’ demands. The minimum width requirement should be based on considerations related to traffic movement and access rather than to parking.

The second suggested policy reform is to eliminate the double standard between public and private streets and make parking optional for residential streets. These policy initiatives would eliminate excessive parking spaces, mitigate associated externalities, correct market distortions, and avoid shifting risks from local governments to families.

According to the research, local residential streets normally cost between $8.20 and $11.10 per square foot to construct and between 17 cents and 75 cents per square foot to maintain annually. If a single parking lane is assumed to be eight feet wide, these parking spaces would require between $1 trillion and $21 trillion in capital costs, as well as annual maintenance costs between $20 billion and $177 billion, or between one and 11 percent of annual local government spending in the United States (US Census 2011).

“These numbers are somewhat artificial because the 2.8 million miles of US local streets were constructed over the course of many years and because costs differ from year to year,” said Dr. Guo. “However, they still provide a reasonable estimate of the investment scale. In comparison, the total capital and operational spending on public transit in the US in 2009 was only $57 billion, according to the American Public Transportation Association.”

The complete report can be downloaded at no charge from transweb.sjsu.edu/project/1001-2.html


Zhan Guo, PhD, is an assistant professor of urban planning and transportation policy at the Wagner School of Public Service, New York University. He studies transportation and land use, public transit, and pedestrian behavior. He is interested in understanding the multiple travel options faced by individual travelers and how government policies could affect the availability of these options and the subsequent individual decisions.

Charles Rivasplata, PhD, is a lecturer in the Urban and Regional Planning Department at San José State University, where he has taught local and regional transport planning classes since 2007. He is a senior transport planner at the San Francisco Municipal Transportation Agency, largely focusing on transportation policy analysis. He earned master’s degrees in civil engineering and in city and regional planning from the University of California, Berkeley, and a PhD in transportation policy from UC Davis.

Richard Lee, PhD, AICP, is a lecturer in the Urban and Regional Planning Department at San José State University and has been a research associate with the Mineta Transportation Institute for over 15 years. Dr. Lee is also an associate with Fehr & Peers, and he has over 25 years of experience as a transportation consultant and academic. He earned his master’s degrees in civil engineering and in city and regional planning, and his PhD in city and regional planning, all from the University of California, Berkeley.

David Keyon is a master of urban and regional planning student at San José State University, concentrating in land use and transportation. He worked over seven years as a development review planner in California prior to returning to school in 2010. David has an interest in public transportation planning.

Luis Schloeter is a second-year urban planning student at the Wagner Graduate School of Public Service at New York University, where he specializes in international development planning. He holds a bachelor’s degree in political science from Universidad Rafael Urdaneta, Venezuela, where he graduated with honors.


The Mineta Transportation Institute (MTI) conducts research, education, and information and technology transfer, focusing on multimodal surface transportation policy and management issues, especially as they relate to transit. MTI was established by Congress in 1991 as part of the Intermodal Surface Transportation Efficiency Act (ISTEA) and was reauthorized under TEA-21 and again under SAFETEA- LU. The Institute has been funded by Congress through the US Department of Transportation’s (DOT) Research and Innovative Technology Administration, by the California Legislature through the Department of Transportation (Caltrans), and by other public and private grants and donations, including grants from the US Department of Homeland Security. DOT selected MTI as a National Center of Excellence following competitions in 2002 and 2006. The internationally respected members of the MTI Board of Trustees represent all major surface transportation modes. MTI’s focus on policy and management resulted from the Board’s assessment of the transportation industry’s unmet needs. That led directly to choosing the San José State University College of Business as the Institute’s home.


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