How Unscientific Parking Mandates Have Created and Enforced Car Dominance

Colin Fiske, Coalition for Responsible Transportation Priorities Executive Director

This is the fifth in a series of articles in the EcoNews about the history of how American communities were designed for cars. The first four articles described the origins of traffic laws, the criminalization of walking in the street, the rise of zoning laws that led to segregated, car-dominated communities, and the impacts of the Interstate Highway System.

In 1956, the same year that President Eisenhower signed the law that created the Interstate Highway System, another, less famous but arguably even more influential document was also produced by the nascent federal transportation bureaucracy: the Bureau of Public Roads (later renamed the Federal Highway Administration) published the innocuously titled Parking Guide for Cities. By that time, many cities had already adopted laws requiring new homes and businesses to provide off-street parking spaces. The Bureau’s guide, however, was the first systematic attempt to justify these requirements, and its endorsement of the practice was hugely influential. Roughly a decade later, in 1968, an analysis by the Federal Highway Administration showed that the number of parking spaces per capita was increasing dramatically in almost all American cities. 

The rapid increase in the number of local parking mandates and the number of actual parking spaces wasn’t solely the result of one document, of course. The Parking Guide for Cities reflected attitudes toward parking that were widespread among planners and policy-makers of that era. A 1971 report called “Parking Principles” from the Highway Research Board, part of the prestigious National Academy of Sciences, revealed these attitudes and assumptions clearly. The report treated the increasing amount of driving done by Americans as an unalterable fact and argued that the need for off-street parking was a natural consequence. Interestingly, planners of the time often also viewed off-street parking partly as a replacement for on-street parking that would allow them to increase travel lanes, allow more driving, and reduce collisions associated with parking. Eventually, however, on-street parking became almost as sacrosanct in transportation planning as off-street parking, as any observer of a modern city street can plainly see. 

The 1971 Highway Research Board report included recommendations of specific parking mandates for local governments to adopt into their zoning codes: 2 spaces for each single-family home, 3.3 spaces per thousand square feet of floor area for banks, 0.3 spaces per seat for a church, and so on. This attempt to codify the number of parking spaces that should be required for a given land use was fully institutionalized in 1985 with the publication of the first Parking Generation Manual by the Institute of Transportation Engineers. (Readers of this series will recall that the Institute has played a major role in promoting many other policies and plans that prioritized cars over other modes of transportation as well.) The Manual contains precise estimates of parking “demand” for every conceivable land use. The latest edition was published in 2019, and it continues to provide the basis for most of the parking mandates adopted into local zoning codes.

UCLA Professor Donald Shoup, widely regarded as the world’s foremost expert on parking policy, has dedicated much of his career to debunking these estimates of parking “demand.” He has shown that most of the estimates provided in the Parking Generation Manual and adopted into local zoning codes are based on a small number of observations that have no scientific or statistical validity. Moreover, according to Shoup’s 2005 book The High Cost of Free Parking, the observations are almost always done in places with unlimited free parking and no public transit at times of peak demand (e.g., Black Friday at a shopping mall), meaning that they reflect the maximum conceivable requirements.

Following up on Shoup’s debunking of the theoretical basis for parking mandates, recent research has confirmed what many observers have long suspected: instead of parking “demand” being a natural consequence of supposedly independent decisions to drive cars everywhere, the availability of abundant, free parking actually causes more people to own cars and to drive. In other words, the last 75 years of parking mandates—based on evidence pulled mostly from thin air—helped create the world that they claimed already existed.

Now, we all live in a world dominated by parking. A recent study estimated that 14 percent  of land in incorporated parts of Los Angeles County—about 200 square miles—is devoted to parking.  And despite its car-centric reputation, Los Angeles is not an outlier. According to research from the Research Institute for Housing America, Jackson, Wyoming has 27 times more parking spaces than homes, and in Seattle there are more than twice as many parking spaces per acre as there are people. Local governments barely have to require parking anymore: it’s become so expected that the banks that finance development often insist on including it in their projects.

Devoting vast areas of land to storage for vehicles not only subsidizes and encourages more driving, it also makes other modes of transportation less appealing. It’s difficult to keep people’s homes close enough to where they work, shop, or go to school for them to walk or bike, for example, when every building is surrounded by a sea of parking many times the size of the building itself. And it’s expensive: parking drives up the cost of construction, which—as Professor Shoup likes to point out—is passed onto the rest of us in the form of higher prices for everything else, from housing to groceries. A single garage parking space can add almost 20 percent  to an apartment’s rent—whether the renter owns a car or not.

After many years of efforts by advocates, some progress is now being made toward eliminating unscientific parking mandates. The Parking Reform Network maintains an ever-growing list of cities nationwide that have eliminated their mandates, and a new law in California will prohibit parking requirements from being enforced near high-quality public transit. But major obstacles remain. Recently, an outcry from business owners kept the City of Eureka from turning several city-owned parking lots into affordable housing. Clearly a lot more will need to be done to remake our communities in ways that prioritize people over automobiles.

Recommended Reading:

  • Manville, Michael. 2021. How Parking Destroys Cities. The Atlantic.
  • Shoup, Donald. 2005. The High Cost of Free Parking. Routledge.
  • Oliver, Ned. 2022. Secret parking minimums are driving up development costs. Axios.
  • Gabbe, CJ and Greg Pierce. 2017. The Hidden Cost of Bundled Parking. Access Magazine.