Parking requirements are the dark matter of the urban universe: they affect transport and land use in mysterious ways. These fun facts illustrate the costs and impacts of economically excessive parking supply.
[Updated February 5, 2018] Last Thursday evening a buddy and I walked to the Fernwood Inn, our local pub, but the place was full! On a weekday! Our neighborhood needs more pubs!
Virtually everybody benefits from more local businesses that are easy to access by walking and cycling because this reduces traffic congestion, parking problems and impaired driving, and by reducing transportation expenses, leaves residents with more money to spend on local goods. Many entrepreneurs would love to establish new businesses in our neighborhood, but there is one major obstacle: excessive parking requirements. The city's zoning code requires one parking space per three seats in neighborhood pubs, one of the highest requirements of any land use category. The Inn has 136 seats, and so a new equivalent pub would require 44 parking spaces, or about a third of an acre of land, more than the building's footprint.
This is schizophrenic: on one hand traffic safety campaigns discourage drinking and driving, but on the other hand, local zoning codes ensure that it is easy to drive to restaurants, bars, and pubs, even those located in walkable neighborhoods. Increasing businesses' land requirements creates a self-fulfilling prophecy, it discourages development in walkable urban neighborhoods and forces businesses to develop in sprawled, automobile-dependent urban fringe areas where land is cheaper. Stupid!
Excessive, inflexible parking requirements contradict virtually every principle of good planning: they create ugliness, increase development costs, reduce housing affordability, reduce economic productivity and tax revenue per unit of land, encourage automobile ownership and use, increase impervious surface area and urban heat island effects, stimulate sprawled development, and result in huge and regressive subsidies from people who drive less than average to those who drive more than average.
However, vehicle parking is so ubiquitous that it is generally invisible, like water is to fish. Most people have no idea of the economic, social and environmental costs caused by the pursuit of convenient parking. So, to put these impacts into perspective here are some fun facts that you can use to communicate the cost, waste and inequity of current parking planning practices.
How big is a parking space?
A typical parking space is 8-10 feet (2.4-3.0 meters) wide and 18-20 feet (5.5-6.0 meter) long, totalling 144-200 square feet (13-19 sq. meters). Off-street parking requires driveways and landscaping, and so typically requires 250-350 square feet (25-35 square meters) per space, allowing 125-175 spaces per acre (250-450 per hectare).
How many parking spaces exist in the United States?
Various studies have estimated the number of parking spaces per vehicle and the total amount of land devoted to vehicle parking in specific areas. Davis, et al. used detailed aerial photographs to estimate the number of surface lot parking spaces in Illinois, Indiana, Michigan, and Wisconsin. Parking lots were identified as paved surfaces with stripes painted on the surface or where more than three cars were parked in an organized fashion, which excluded on-street and structured parking spaces (other than the top floor if the structure has an open roof), and residential parking spaces not in parking lots. They identified more than 43 million parking spaces in these four states, which averages 2.5 to 3.0 off-street, non-residential spaces per vehicle. Another study, by Pijanowski also found approximately three non-residential off-street parking spaces per vehicle in Tippecanoe County, a typical rural community. These studies suggest that, including structured and residential parking, there are four to five government-mandated off-street parking spaces per motor vehicle. Since there are approximately 260 million motor vehicles in the U.S., this suggests that there are more than a billion off-street parking spaces in the United States.
How much land is devoted to parking?
Akbari, Rose and Taha used high-resolution orthophtos to estimate the area of various land-use types in Sacramento, California. They found that road and parking facilities covered 28 percent of of land area in residential areas and up to 68 percent of land in commercial areas. Similarly, McCahill and Garrick found that roads and parking facilities cover about 35% of the surface area of most residential areas and 50–70% in most non-residential areas in 12 typical U.S. cities.
According to a major study, Parking Infrastructure: A Constraint on or Opportunity for Urban Redevelopment? A Study of Los Angeles County Parking Supply and Growth, 14% of Los Angels land is devoted to parking. Their results are illustrated below.
Assuming four 300 square-feet off-street parking spaces per motor vehicle, each vehicle requires about 1,200 square feet of land for parking. That is more than the amount of land devoted to an average house, or enough land to produce a half-million calories of potatoes.
What is the monetary value of these parking spaces?
Parking facilities require land, construction, and operating costs. Land costs vary from just a few hundred dollars per space in rural areas to tens of dollars per acre in attractive and economically successful urban areas. A typical surface parking space costs $5,000-10,000, and structured and underground parking spaces cost $20,000 to $80,000 [pdf] in construction costs. Meeting parking requirements typically adds 10% to building costs, and even more in urban areas with high land prices, where a single $50,000 parking space can add 20% to the costs of a lower-priced apartment.
In total, typical urban parking spaces have annualized costs of $800-3,000 [pdf]; that is the amount that a owners would need to charge to fully recover their total land, construction and operating costs.
Many vehicles are worth less than the parking space they occupy, particularly structured and underground parking, and most vehicles are worth less than the total sum of parking spaces required by law to serve them.
Assuming there are on average 4.5 government-mandated off-street spaces per vehicle, with $1,000 average annual costs, each motor vehicle requires $4,500 worth of parking annually, which is slightly more than the $4,415 that consumers spend annually per vehicle. (According to the U.S. Consumer Expenditure Survey, an average household owns 1.9 vehicles and spends $9,049 annually on transportation, of which $660 is for public transport.) Since there are approximately 260 million vehicles in the United States, this suggests that off-street, government mandated parking costs exceed $1.0 trillion annually.
Who pays for vehicle parking?
Most (estimated at 99% [pdf]) parking is unpriced and therefore subsidized, paid indirectly through taxes and building rents, which adds to the costs of goods and services: our beer is more expensive to pay for parking at our pub. According to one estimate [pdf], there are approximately 20 million priced parking spaces, representing about three percent of all spaces and generating about $25 billion in revenue.
Since U.S. households own, on average, 1.9 vehicles [pdf], this suggests that a typical household spends more than $8,000 annually to subsidize parking though housing costs, taxes and retail prices, and lower wages and worker benefits to pay for commuter parking. As a result, households that own fewer than average vehicles tend to subsidize the parking costs of households that own more than average vehicles, and since vehicle ownership tends to increase with income [pdf], this is regressive: lower-income households tend to subsidize the parking costs of their more affluent neighbors.
How does parking underpricing affect traffic problems?
If, rather than paying indirectly, motorists pay directly for parking, or free parking is cashed out (travelers who do not drive receive the cash equivalent of parking subsidies offered to motorists), vehicle trips typically decline by 10-30% [pdf], indicating that about 10-30% of traffic congestion, collisions, and pollution problems are caused by government parking requirements that result in abundant and cheap parking at the expense of other goods (housing, food and drink) and other travel modes.
How many parking spaces do communities really need?
How long is a piece of string?
There are several possible ways to determine the optimal number of parking spaces for a particular location:
- Most traffic engineers seem to assume that parking should generally be abundant and cheap. As a result, their methods tend to favor oversupply. Most parking generation studies are performed in automobile-dependent locations, based on 85th percentile demand curves (which means that 85 out of 100 sites will have unoccupied parking spaces even during peak periods), use an 85th occupancy rate (a parking facility is considered full if 85% of spaces are occupied), and a 10th design hour (parking facilities are sized to fill only ten hours per year). These practices result in more parking spaces than are actually needed at most destinations, particularly in transit oriented and smart growth communities, or where transportation [pdf] and parking management programs [pdf] are implemented.
- To economists, optimal parking supply is the number of spaces that motorists are willing to pay for, with cost-recovery prices (revenues pay the full costs of providing parking). From this perspective, in most places (excepting a few older downtowns) parking is severely underpriced and oversupplied.
- To planners, optimal parking supply is the amount consistent with a community's strategic goals. Abundant and subsidized parking might help support local economic development goals and reduce spillover parking problems (motorists parking in undesirable locations), but these goals can often be achieved with fewer but better managed parking, which tends to support most other community goals including increased affordability and productivity, reduced parking problems, and more efficient land development. As a result, most planners support parking policy reforms.
How can parking be more accurate and efficient?
Planners can often significantly reduce parking requirements by applying adjustment factors that reflect geographic conditions and management strategies. The table below summarizes examples of these adjustment factors. These can be incorporated into zoning codes so parking requirements are automatically adjusted downward to be more accurate and economically efficient.
Geographic Location. Vehicle ownership and use rates in an area.
Adjust parking requirements to reflect variations identified in census and travel survey data. 40-60% reductions are often justified in Smart Growth neighborhoods.
Residential Density. Number of residents or housing units per acre/hectare.
Reduce requirements 1% for each resident per acre (e.g. 15% where at 15 residents per acre and 30% at 30 res. per acre).
Employment Density. Number of employees per acre/hectare.
Reduce requirements 10-15% in areas with 50 or more employees per gross acre.
Land Use Mix. Land use mix located within convenient walking distance.
Reduce requirements 5-15% in mixed-use developments. Additional reductions with shared parking.
Transit Accessibility. Nearby transit service frequency and quality.
Reduce requirements 10% within ¼ mile of frequent bus service, and 20-50% within ¼ mile of a rail transit station.
Carsharing. Whether carsharing services are located within or nearby a building.
Reduce residential requirements 10-20% if carshare vehicles are located onsite, or 5-10% if located nearby.
Walkability and bikeability. Walking environment quality.
Reduce requirements 5-15% in very walkable and bikeable areas, and substitute bike parking for up to 10% of car parking.
Demographics. Age and physical ability of residents or commuters.
Reduce requirements 20-40% for housing for young (under 30), elderly (over 65) or disabled people.
Income. Average income of residents or commuters.
Reduce requirements 10-20% for the 20% lowest income households, and 20-40% for the lowest 10%.
Housing Tenure. Whether housing is owned or rented.
Reduce requirements 20-40% for rental versus owner-occupied housing.
Pricing. Parking that is priced, unbundled or cashed out.
Reduce requirements 10-30% for cost-recovery pricing (i.e. fees that pay the full cost of parking facilities), and 10-20% for unbundling (parking rented separate from building space).
Sharing/overflow. Ability to share parking facilities with other nearby land uses.
Depends on the differences in peak demands with other land use. 20-40% reductions are often possible.
Management programs. Parking and mobility management programs implemented at a site.
Reduce requirements 10-40% at worksites with effective parking and mobility management programs.
Design Hour. Number of allowable annual hours a parking facility may fill.
Reduce requirements 10-20% if a 10th annual design hour is replaced by a 30th annual peak hour. Requires overflow plan.
Contingency-Based Planning. Use lower-bound requirements, and implement additional strategies if needed.
Reduce requirements 10-30%, and more if a plan exists indicating the responses that will be deployed if the number of parking spaces initially built is insufficient in the future.
What do current parking policies indicate about community priorties?
Despite problems with homelessness and housing inaffordability, no communities have laws that guarantee free housing for people, but nearly all jurisdictions have laws that mandate abundant, and usually free housing for vehicles, in the form of unpriced on-street parking and off-street parking requirements in zoning codes. These policies conflict: the more parking spaces we require for residential development, the fewer housing units that can be built in a given area, and the less affordable housing will be.
What does this mean for planners?
If you want job security as a planner, become the local expert on parking policy reforms and efficient parking management strategies.
What do we want? More efficient parking management!
When do we want it? Now!!
For More Information
International Conference on Parking Reforms for a Livable City, Centre for Science and Environment (www.cseindia.org), 17 August 2011, New Delhi.
Michael Kodransky and Gabrielle Hermann (2011), Europe’s Parking U-Turn: From Accommodation to Regulation, Institute for Transportation and Development Policy.
Todd Litman (2017), Parking Management: Comprehensive Implementation Guide, Victoria Transport Policy Institute.
Todd Litman (2011), “Why and How to Reduce the Amount of Land Paved for Roads and Parking Facilities,” Environmental Practice, Vol. 13, No. 1, March, pp. 38-46.
Vinit Mukhija and Donald Shoup (2006), “Quantity Versus Quality in Off-Street Parking Requirements,” Journal of the American Planning Association, Vol. 72, No. 3, Summer, pp. 296-308.
Parking Reform promotes various parking policy reforms.
Donald Shoup (1999b), “The Trouble With Minimum Parking Requirements,” Transportation Research A, Vol. 33, No. 7/8, Sept./Nov., pp. 549-574.
Patrick Siegman (2008), Less Traffic, Better Places: A Step-by-Step Guide to Reforming Parking Requirements, San Diego Section of the American Planning Association.
Mott Smith (2006), Onsite Parking: The Scourge of America's Commercial Districts, Planetizen.
Ruth Steiner, et al. (2012), Impact of Parking Supply and Demand Management on Central Business District (CBD) Traffic Congestion, Transit Performance and Sustainable Land Use, Florida DoT Research Center.
Richard Willson (2015), Parking Management for Smart Growth, Island Press.
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