Not enough parking, you say? A study of garage use and parking supply for single-family homes in Sacramento and implications for ADUs
Keywords:Parking, Garage, Accessory Dwelling Units, Single-Family Home
Accessory dwelling units (ADUs) are increasingly touted as part of the solution to the intransigent housing shortages facing many metropolitan areas across the United States. But numerous barriers to ADU development persist, including opposition by neighboring households. One persistent question is whether ADU residents would overwhelm on-street parking in the predominately single-family neighborhoods where ADUs are typically built. That question is difficult to answer because there is a surprising dearth of research on the effective parking supply in single-family neighborhoods. We use a survey of homeowners in Sacramento, California, to investigate the supply and sufficiency of residential parking for single-family homes, including how households actually use their garages, and help answer the ADU parking conundrum. After estimating and accounting for actual garage use, we find that more than 75% of households have enough off-street parking available to park all their vehicles. When we combine off-street and on-street parking supplies, we find that households have an average of 1.6 more parking spaces available to them than they have vehicles. That parking surplus is more than enough to accommodate the average ADU tenant and their vehicle, belying claims that ADUs will overwhelm existing parking supplies in single-family neighborhoods.
Anacker, K. B., & Niedt, C. (2019). Classifying regulatory approaches of jurisdictions for accessory dwelling units: The case of Long Island. Journal of Planning Education and Research. https://doi.org/10.1177/0739456X19856068
Anirudh, B., Mazumder, T. N., & Das, A. (2021). A contemporary review of residential parking lessons for Indian cities. Housing Policy Debate. https://doi.org/10.1080/10511482.2021.1909630
Arnold, J., Graesch, A., Ragazzini, E., & Ochs, E. (2012). Life at home in the twenty-first century: 32 families open their doors. Los Angeles: Cotsen Institute of Archaeology Press.
Arnold, J. E., & Lang, U. A. (2007). Changing American home life: Trends in domestic leisure and storage among middle-class families. Journal of Family and Economic Issues, 28, 23–48. https://doi.org/10.1007/s10834-006-9052-5
Barrington-Leigh, C., & Millard-Ball, A. (2015). A century of sprawl in the United States. Proceedings of the National Academy of Sciences, 27, 8244–8249. https://doi.org/10.1073/pnas.1504033112
Brown, A., Mukhija, V., & Shoup, D. (2017). Converting garages into housing. Journal of Planning Education and Research 40, 56–68. https://doi.org/10.1177/0739456X17741965
Brown, M. (2007). Shifting landscapes of mobility: Reconfiguring space in the mission district for automobiles (master’s thesis), San Francisco State University. Retrieved from https://marybrown.files.wordpress.com/2008/01/introduction_toc.pdf
Brown, M. J., & Palmeri, J. (2014). Accessory dwelling units in Portland, Oregon: Evaluation and interpretation of a survey of ADU owners. Salem, OR: Department of Environmental Quality. Retrieved from https://accessorydwellings.files.wordpress.com/2014/06/adusurveyinterpret.pdf
California Assembly Bill 881. (2019-2020). Chapter 659 (Cal. Stat. 2019). Retrieved from
California Department of Finance. (2019). E-1 population estimates for cities, counties and the state with annual percent change — January 1, 2018 and 2019. Sacramento, CA: California Department of Finance.
California Government Code. (n.d.). Title 7, Division 1, Section 65852.2. Retrieved from https://codes.findlaw.com/ca/government-code/gov-sect-65852-2.html
California Vehicle Code. (n.d.). Division 11, Section 22507.2. Retrieved from https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=VEH§ionNum=22507.2
California Vehicle Code. (n.d.) Division 11, Section 22508. Retrieved from https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=VEH§ionNum=22508.
Casey, D. (2020). COVID-19 stopped the economy, but our housing shortage remains. CaRLA continues to fight for the answer to both: ADUs. Retrieved from https://carlaef.org/2020/04/16/covid-19-stopped-the-economy-but-our-housing-shortage-remains-carla-continues-to-fight-for-the-answer-to-both-adus/
Chapple, K., Lieberworth, A., Ganetsos, D., Valchuis, E., Kwang, A., & Schten, R. (2020). ADUs in California: A revolution in progress. Berkeley, CA: UC Berkeley Center for Community Innovation. Retrieved from https://www.aducalifornia.org/wp-content/uploads/2020/10/ADU-Progress-in-California-Report-October-Version.pdf
Chapple, K., Wegmann, J., Mashhood, F., & Coleman, R. (2017). Jumpstarting the market for accessory dwelling units: Lessons learned from Portland, Seattle and Vancouver. Berkeley, CA: UC Berkeley Terner Center for Housing Innovation, UC Berkeley Center for Community Innovation, and the Urban Land Institute. Retrieved from https://ternercenter.berkeley.edu/wp-content/uploads/pdfs/Jumpstarting_the_Market_--_ULI.pdf
Chapple, K., Wegmann, J., Nemirow, A., & Dentel-Post, C. (2012). Yes in my backyard: Mobilizing the market for secondary units. Berkeley, CA: UC Berkeley Center for Community Innovation. Retrieved from https://communityinnovation.berkeley.edu/sites/default/files/yes_in_my_backyard_mobilizing_the_market_for_secondary_units.pdf?width=1200&height=800&iframe=true
Chavez, S., & Quinn, J. (1987). Substandard housing: Garages: Immigrants in, cars out. Los Angeles Times. Retrieved from https://www.latimes.com/archives/la-xpm-1987-05-24-mn-2558-story.html
Chester, M., Horvath, A., & Madanat, S. (2010). Parking infrastructure: Energy, emissions, and automobile life-cycle environmental accounting. Environmental Research Letters, 5, 034001. https://doi.org/10.1088/1748-9326/5/3/034001
Cho, J. (2016). Second units in the Silicon Valley. The Urban Lawyer, 48, 459–488.
Retrieved from https://www.jstor.org/stable/44648239?refreqid=excelsior%3Ac5adb6bbd311283df814e142087899df
City of Sacramento. (2021a). Accessory dwelling units. Retrieved from https://www.cityofsacramento.org/Community-Development/Resources/Accessory-Dwelling-Units
City of Sacramento. (2021b). 2021–2029 housing element. Retrieved from https://www.cityofsacramento.org/-/media/Corporate/Files/CDD/Planning/Long-Range/Housing-Element/00_Sac-HE_Amended_Final_Dec142021.pdf?la=en
City of Sacramento. (2021c). Residential parking permit program. Retrieved from http://www.cityofsacramento.org/public-works/parking-services/street-parking/parking-permits/Residential
City of Sacramento. (n.d.). Planning and development code map book. Retrieved from https://www.cityofsacramento.org/-/media/Corporate/Files/CDD/Planning/Maps/ZoningDefinitions.pdf?la=en
City of Sacramento. (n.d.). Planning and development code. Section 17.508.050. Retrieved from https://www.qcode.us/codes/sacramento/view.php?topic=17-v-17_508-17_508_050
City of Sacramento. (n.d.). Planning and development code. Section 17.608.040(F)(2)(a). Retrieved from https://www.qcode.us/codes/sacramento/view.php?topic=17-vi-17_608-17_608_040
City of Sausalito. (2011). Accessory dwelling unit survey technical report: Two-family and multi-family zoning districts. Retrieved from https://www.sausalito.gov/home/showpublisheddocument/9557/636326254065130000
Garrison, J. (2009). Compton cracking down on illegal garage conversions. Los Angeles Times. Retrieved from https://www.latimes.com/archives/la-xpm-2009-may-06-me-compton-garages6-story.html
Gebhardt, M., Gilden, B., & Kidron, Y. (2018). Accessory dwelling units in Portland, Oregon ISS survey 1st report. (Report No. 118). Portland, OR: Institute for Sustainable Solutions Publications and Presentations, Portland State University. Retrieved from https://pdxscholar.library.pdx.edu/cgi/viewcontent.cgi?article=1119&context=iss_pub
Guo, Z. (2013). Residential street parking and car ownership. Journal of the American Planning Association 79, 32–48. https://doi.org/10.1080/01944363.2013.790100
Guo, Z., Rivasplata, C., Lee, R., Keyon, D., & Schloeter, L. (2012). Amenity or necessity? Street standards as parking policy (MTI Report 11-23). San Jose, CA: Mineta Transportation Institute, San Jose State University. Retrieved from https://transweb.sjsu.edu/sites/default/files/1001-2-street-standards-street-width-parking-policy-investigation.pdf
Guo, Z., & Schloeter, L. (2013). Street standards as parking policy: Rethinking the provision of residential street parking in American suburbs. Journal of Planning Education and Research, 33, 456–470. https://doi.org/10.1177/0739456X13504299
Jenks, M., and Noble, J. (1996). Parking: Demand and provision in private sector housing development.Oxford, UK: Oxford Brookes University.
Kalton, G., & Flores-Cervantes, I. (2003). Weighting methods. Journal of Official Statistics, 19, 81–97.
Morales, R. (2019). Evaluating accessory dwelling unit (ADU) friendliness: The case of the San Gabriel Valley [Master’s thesis]. California State Polytechnic University, Pomona, CA. Retrieved from https://scholarworks.calstate.edu/concern/theses/kk91fn80x?locale=en
Pfeiffer, D. (2019). Regulating ADUs in California: Local approaches & outcomes. Berkeley, CA: UC Berkeley Terner Center for Housing Innovation. Retrieved from https://californialanduse.org/download/Pfeiffer_Regulating_ADUs_in_California.pdf
RAC Media Center. (2021). Nearly six million UK garages not used for cars as they’re too full of junk. Retrieved from https://media.rac.co.uk/pressreleases/nearly-six-million-uk-garages-not-used-for-cars-as-theyre-too-full-of-junk-3112460
Roth, D. (2016). A review of the residential parking management program in Bellevue, WA [Master’s thesis]. University of Washington, Seattle. Retrieved from https://digital.lib.washington.edu/researchworks/bitstream/handle/1773/36857/Roth_washington_0250O_15900.pdf?sequence=1
Sacramento County. (2020). Sacramento County open data: Parcels. Retrieved from https://data.saccounty.gov/datasets/sacramentocounty:parcels/about
Scheiner, J., Faust, N., Helmer, J., Straub, M., & Holz-Rau, C. (2020). What’s that garage for? Private parking and on-street parking in a high-density urban residential neighborhood. Journal of Transport Geography, 85, 102714. https://doi.org/10.1016/j.jtrangeo.2020.102714
Schlossberg, M., & Amos, D. (2015). Rethinking residential on-street parking. In E. Talen (Ed.), Retrofitting sprawl: Addressing 70 years of failed urban form (pp. 181-198). Athens, GA: University of Georgia Press.
Taylor, E. J. (2020). Parking policy: The politics and uneven use of residential parking space in Melbourne. Land Use Policy, 91, 103706. https://doi.org/10.1016/j.landusepol.2018.11.011
Thigpen, C., & Volker, J. (2017). Repurposing the paving: The case of surplus residential parking in Davis, CA. Cities, 70, 111–121. https://doi.org/10.1016/j.cities.2017.06.020
United Kingdom Department for Transport. (2007). Manual for streets. London: Thomas Telford Publishing.
US Census Bureau. (2018a). 1-year American community survey estimates. Washington, DC: US Census Bureau.
US Census Bureau. (2018b). 5-year American community survey estimates. Washington, DC: US Census Bureau.
US Census Bureau. (2017). 1-year American community survey estimates. Washington, DC: US Census Bureau.
US Census Bureau. (2010). Decennial census. Washington, DC: US Census Bureau.
US Census Bureau. (2003a). Census 2000, public use microdata sample (PUMS), United States. Washington, DC: US Census Bureau.
US Census Bureau. (2003b). Census 2000, public use microdata sample, (PUMS), United States [Technical documentation]. Washington, DC: US Census Bureau.
Volker, J. (2020). Exploring the changing faces of housing development and demand in California: Millennials, casitas, and reducing VMT [doctoral dissertation]. University of California, Davis. Retrieved from https://www.proquest.com/openview/86f78eeb9e9ae237d7a34bb90e5c45a4/1?pq-origsite=gscholar&cbl=51922&diss=y
Volker, J. M. B., & Handy, S. (in press). Exploring homeowners' openness to building accessory dwelling units in the Sacramento Metropolitan Area. Journal of the American Planning Association. https://doi.org/10.1080/01944363.2022.2036222
Volker, J. M. B., Lee, A. E., & Fitch, D. T. (2019). Streamlining the development approval process in a post–level of service Los Angeles. Journal of the American Planning Association, 85, 114–132. https://doi.org/10.1080/01944363.2019.1601587
Voulgaris, C. T., Taylor, B. D., Blumenberg, E., Brown, A., & Ralph, K. (2016). Synergistic neighborhood relationships with travel behavior: An analysis of travel in 30,000 US neighborhoods. Journal of Transportation and Land Use, 10, 437–461. https://doi.org/10.5198/jtlu.2016.840
Wegmann, J. (2015). Research notes: The hidden cityscapes of informal housing in suburban Los Angeles and the paradox of horizontal density. Buildings & Landscapes, 22, 89–111.
Wegmann, J., & Chapple, K. (2012). Understanding the market for secondary units in the East Bay. (No. 2012–03). Berkeley, CA: UC Berkeley Institute of Urban and Regional Development. Retrieved from https://escholarship.org/uc/item/9932417c
Wheeler, S. M. (2015). Built landscapes of metropolitan regions: An international typology. Journal of the American Planning Association, 81, 167–190. https://doi.org/10.1080/01944363.2015.1081567
Willson, R. (2000). Reading between the regulations: Parking requirements, planners’ perspectives, and transit. Journal of Public Transportation, 3, 111–128. https://doi.org/10.5038/2375-0901.3.1.6
Woetzel, J., Mischke, J., Peloquin, S., & Weisfield, D. (2016). A tool kit to close California’s housing gap: 3.5 million homes by 2025. New York: McKinsey Global Institute. Retrieved from https://www.mckinsey.com/~/media/mckinsey/industries/public%20and%20social%20sector/our%20insights/closing%20californias%20housing%20gap/closing-californias-housing-gap-full-report.pdf
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