High Density Housing--Impact on Neighborhood Parking

 

By 2040, the City of San Francisco’s population will increase by more than 200,000. Much of this growth will occur in the City’s eastern neighborhoods, (including South of Market (SoMa), Mission Bay, Potrero Hill and Dogpatch) in the form of large, mixed-use buildings with limited or no on-site parking.

These targeted growth areas encompass several Residential Permit Parking (RPP) Areas which were established to mitigate the negative impacts of large traffic generators, such as hospitals, universities, transit stations and entertainment venues on residential neighborhoods. 

New, higher-density development is creating greater demand for on-street parking than what the RPP program was designed to address. Typical residential parking restrictions cannot meet the varied needs of customers, employees, visitors and others needing on-street parking. Alternative means of parking management are needed to meet the increasing demand for on-street parking by non-residents, while preserving residents’ access to parking close to their homes.  This will require significant changes in those RPP Areas impacted by new, higher-density development. 

To better understand the potential impacts of changes to the way the SFMTA manages parking in transitioning neighborhoods, the SFMTA’s Parking and Curb Management Group completed a study of residents’ travel and parking behavior in areas targeted for new growth.  Existing research has found that managing parking supply at the workplace is an effective means of encouraging use of alternative commute modes. There is no substantial body of research, however, that addresses whether the supply of parking in residential areas affects the use or ownership of personal vehicles.  This study will help to close this knowledge gap. The SFMTA is also interested in knowing how keeping RPP in areas targeted for high density development might impact the effectiveness of recent parking policy changes aimed at reducing vehicle ownership.

Towards that end, the SFMTA is studying the link between parking availability and vehicle ownership within rapidly transitioning urban neighborhoods in San Francisco. The study includes a literature review and data from five components: a survey mailed to more than 18,000 households in 118 buildings with 50 or more units; a telephone survey of 111 building managers; a study of on-street parking utilization in the study neighborhoods; and, an analysis of residents’ use of the RPP program.

The purpose of the household survey was to generate information about residents’ travel modes (transit, car share, walk, bike, etc.), vehicle ownership, and vehicle parking.  Survey findings will assist the SFMTA in developing policy solutions towards addressing parking management in areas impacted by significant new housing development. 

Some of the research questions that the SFMTA is addressing through this study are:

1. Does availability of parking in residential areas affect vehicle ownership?
2. Do the City of San Francisco’s policies on parking supply affect vehicle ownership?
3. Do residents of buildings located within an RPP area have higher vehicle ownership rates than residents not within an RPP area?
4. What is the likely impact of parking policy changes on families and how do these impacts vary by income or household size?  

Study Design

The Study has six components:

• Literature review
• Household survey
• Survey of property managers
• Census analysis
• Parking utilization
• Analysis of RPP permits issued to study area residents

Literature Review

The literature review summarizes findings related to the effects of the built environment and off- and on-street parking policy on vehicle ownership and mode choice. Much of the available research is constrained either by geography, time and/or scope, but it provides valuable insight into broader patterns and helps guide our study of the impact of high-density housing on neighborhood parking, as will be discussed below. Vehicle ownership can be influenced by density, housing type, parking availability, parking convenience and parking cost—which is a product of parking policies like unbundling, parking maximums and RPP. Municipalities can discourage vehicle ownership by zoning for more mixed-use density, limiting off-and on- street supply and pricing parking appropriately in residential areas. Given a lack of recent and locally-specific research, there remains unanswered questions regarding residential parking management, as most parking studies are focused on trip destinations, such as commercial areas, employment centers and entertainment venues. This literature review and our current study aim to fill this gap. Full Literature Review and Bibliography.

Household Survey

The household survey was mailed to residents of multi-family buildings with 50 or more units, located within SoMa, South Beach, Rincon Hill, Mission Bay and Dogpatch.  Selected buildings were divided between RPP Areas and areas not covered by RPP to allow for comparisons.    

The building list was generated using the San Francisco Property Information Map (PIM) online tool provided by the Planning Department.  A total of 118 buildings were selected.  Since surveys were targeted to specific buildings, it was necessary to use a mail survey. An on-line survey was ruled out because it was not possible to identify the building address of an email list generated from voter registration rolls. 

Godbe Research Associates (GRA) administered the survey in fall of 2019 to a total of 18,810 addresses.  From those, the SFMTA received 2,207 valid responses. Individual responses were anonymized and only building-level addresses were provided (no individual unit numbers were provided to SFMTA). Surveys were mailed in four languages: Mandarin Chinese, English, Filipino and Spanish. Residents were asked questions regarding vehicle ownership, travel behavior (such as parking and commuting) along with sociodemographic information. A pre-paid and pre-addressed envelope was included with the surveys and an incentive consisting of an Apple Watch was offered to boost the response rate.

To eliminate the need to ask for respondents’ addresses, each survey was printed with a set of codes to indicate the location of the housing unit.  One of the objectives of the study was to evaluate the differences in vehicle ownership between residents of RPP Areas and other areas not covered by RPP. Another purpose was to evaluate differences between neighborhoods and how variations in access to regional transit affected commute mode and vehicle ownership. We also looked at whether commute, parking and vehicle ownership patterns differed among residents of subsidized and market-rate housing.   

In addition to offering an incentive, efforts to increase the response rate included notices sent to each of the neighborhood and community associations and to the managers of buildings where all units were subsidized with a request for their assistance in promoting the survey to their residents. This additional effort was to mitigate the bias of under sampling residents from low-income households. Vehicle Ownership and Travel Behavior Differences Across Socioeconomic Groups. Full Household Survey results, final crosstabulations and grouped crosstabulations.

Property Manager Survey

Complementing the household survey, property managers of buildings within the study area were surveyed in the summer of 2019 to obtain detailed information regarding overall parking supply, the process of allocating parking among residents, cost of parking, and number of residential units. The intent was to cross-reference data collected through property managers to their residents’ responses to draw relationships between on-site parking supply and cost with vehicle ownership and travel patterns.  In total, there were 118 buildings eligible for the survey from which the SFMTA gathered 112 responses from property managers. This high response rate was achieved through extensive follow-up calls and in-person visits to buildings where property managers were unreachable. This survey was conducted over the phone and, on average, took respondents five to ten minutes to answer. To ensure the accuracy of the data collected, answers were cross-verified with existing San Francisco planning records. Property Manager Survey Results.

Census Analysis

Staff analyzed census data for the study area and San Francisco for comparison with survey data. Factors analyzed include income, housing tenure, race, age, household size and presence of children at the census tract and city level. While our study area boundaries do not precisely capture census tract areas, the census data provides helpful comparisons. The survey results are based on findings from people living in buildings with fifty or more units, whereas the census captures data from people living in any type of housing. In comparison to the census results, respondents to the SFMTA survey were more likely to be homeowners, more likely to have children in the household, and own slightly more vehicles. The census analysis also uncovered variation in income across census tracts, with SoMa showcasing the greatest disparities. Broadly, as compared to the whole of San Francisco, more people reported taking sustainable modes within the study area and owning fewer vehicles. Despite some differences across sociodemographic variables, the SFMTA’s survey results are representative of census findings.  Click here to go to the Census Analysis tables.

Parking Utilization

In April and May 2019, Kittelson and Associates conducted a field survey of parking utilization along four 2-mile routes in SoMa and in Dogpatch.  Parking along each 2-mile route was observed over two days and at 4 times each day: 6:00; 10:00; 2:00; and 8:00.  License plate numbers were collected to determine the origin of the vehicle. This would help in determining the percentage of parked vehicles belonging to residents of the study area or visitors to the area.  In addition, the number of vehicles with valid RPP permits was also collected.  Click here for a summary of the parking occupancy study results.