top of page
  • Writer's pictureBailey Moro

When the Bare Minimum is Too Much: The Self-Exacerbating Feedback Loop of Parking Minimums

In the car-dependent suburb I grew up in, everything we needed on a day-to-day basis was somehow fifteen minutes’ drive from each other. The simple act of “running errands” took up half of the weekend.

Let’s try a little thought experiment: When running errands, why does it take so long? For my family and likely many others’, it’s driving from destination to destination, sitting at traffic lights, hopping across town from one parking lot to another via a series of four-lane roads peppered with far too many intersections.

Think of all the time added back into our week if running errands didn’t take an entire afternoon. Wouldn’t it be so much more efficient if everywhere we needed to go day-to-day were co-located? Why is it that all of our essential errands are so far apart?

Parking minimums are at least part of the answer.

Figure 1: US Route 29, a road that connects miles of parking lots together in Albemarle County, Virginia. Source: NBC 29

Introduction to Parking Minimums

Most local governments, be they municipalities, cities, or counties, have some form of minimum parking requirements. For any type of building, there are a required number of parking spaces the developer must provide, usually based on the size of the building. Like its civilian counterparts, the Federal government is subject to several parking regulations. These include, but are not limited to:

The goal of parking minimums is to provide sufficient off-street parking to satisfy peak demand for the various land uses requiring parking. In theory, this alleviates traffic congestion of cars circling the block, trying to find nearby on-street parking.

These laws became a mainstay of American planning by the middle of the 20th century, as rapidly suburbanizing America was designing every aspect of the built environment for the automobile. In the decades since, millions of acres of land have been devoted to parking lots – it’s estimated that in America today, there are about eight parking spaces for every vehicle in the country, and the combined area of our land dedicated to parking is roughly the size of West Virginia.

The Macro Problem with Parking Minimums

The negative effects of car dependency are well known, but parking minimums receive far less attention, likely due to their technical nature.

Figure 2: Land dedicated to parking in Kansas City, MO. Source: Hayden, Clarkin

First, parking minimums require land uses to supply enough parking to satisfy peak demand, however, peak demand occurs in a relatively small time window, leaving these lots mostly empty throughout the day. Not to mention that the parking provided is most likely free (over 99% of parking in America is free), which results in artificially high demand. The simple price-demand graph tells us this.

Furthermore, critics question the metrics of parking minimums. Most parking minimums tie parking spaces to building square footage, for example, one parking space per 1,000 square feet. But these numbers are rather arbitrary – why does a restaurant need precisely one space per 1,000 square feet? Who decided that was the exact best ratio of parking spaces to square footage?

The answer is simple: a planner either made a judgment call based on trip generation studies, or cited the zoning ordinance of another town (which had to make the same judgment call).

Planning professor and parking economist Donald Shoup has even criticized the Institute of Transportation Engineers’ (ITE) handbooks that are the technical basis of most parking minimums, pointing out that not enough studies were conducted, and they were done at locations in suburban car-dependent towns with free parking, resulting in inflated trip generation and parking demand metrics.

Armed with these high reference numbers, planners passed parking minimums that lead to a vast oversupply of parking. Today, thousands of municipalities across the country rely on these handbooks as the basis for their parking minimums.

The Micro Problem with Parking Minimums

Figure 3: An Aerial of Fort Bragg, NC. Note the amount of land dedicated to surface parking. Source: Google Earth

Parking minimums also present negative effects at the site-specific level.

Cars, and by extension, parking spaces, take up a lot of space. An average parking space requires 330 square feet – this includes the parking bay plus the driving aisle to give the car adequate turning space into the bay. This means that with high parking minimums, more and more of a site must be given up for parking lots. If a building must provide 3 spaces for every 1,000 square feet, the parking lot is already the same size as the building – any higher of a minimum and the lot will be larger than the building.

In America, it’s commonplace for the parking lot to take up far more land than the actual building it serves.

This partly answers the early question of “Why is it that all of our essential errands are so far apart?” Since every land use must provide a certain amount of parking, and the law can require there to be proportionally more parking area than building area, most of the destinations in our communities are simply islands in a sea of parking lots. For many suburban towns, the point of the road network is to allow citizens to get from one parking lot to another quickly.

The Feedback Loop

Parking minimums reinforce our car-dependent culture, and our car-dependent culture reinforces the need for parking minimums.

With ample free parking at nearly every destination we could wish to travel to, we find that driving to each and every destination is the most convenient form of travel, because we know there will be plenty of parking. But, as more of the population travels by car, the demand for parking will rise. This creates the need for a higher parking minimum to ensure peak demand is met. With higher parking minimums, more land is set aside for parking, causing destinations to be further spread apart, requiring driving. This is a positive feedback loop, where one side of the equation exacerbates the other.

To quote Shoup, “Urban planners who rely on these trip generation rates as guides to design the transportation system are therefore planning an automobile-dependent city.” Parking minimums effectively codify car dependency into local law.

Federal Consequences

The Federal government suffers from the effects of parking minimums too. On Federal installations, when every facility has its own dedicated parking lot that is designed to handle more demand than actually exists, there are many negative consequences.

  • Inefficient land use means an installation cannot adequately plan for or accommodate future needs.

  • Spread out facilities may result in operational deficiencies for interdependent functions.

  • Maintaining parking lots can be a large item in O&M budgets, and AT/FP requirements recommend controlled parking, requiring additional expense.

  • It can even lead to unnecessary traffic congestion on-base, as facilities are so far apart the most convenient way between them is driving.

Escaping the Loop

The Schreifer Group specializes in Federal planning and also has extensive experience in transportation planning. Many tactics can be employed to mitigate the consequences of parking minimums on Federal installations and break the feedback loop they create.

Figure 4: A walkable campus with parking on the fringes. Source: TSW Design

First and foremost is simply enabling non-auto forms of transit. At least giving people the option to bike, take transit, or walk is the first step to breaking a car-dependent cycle. For facilities without covered bike racks or easy access to a pedestrian network, this is a low-cost solution that at least creates options for commuters.

Taking the next step would be Transit-Oriented Development (TOD). This is when the design is primarily focused towards non-auto transit, rather than the car. In this scenario, taking transit or biking may be more convenient than driving.

Campus planning is an excellent option to efficiently use land. By centralizing all facilities in a walkable campus, parking can be relegated to the outer fringes. On a walkable campus, you would only park once and be able to walk to every other destination necessary throughout a day. Access roads can be designed for mission-specific vehicles, making campus planning applicable from administrative campuses to industrial centers.

Micromobility is a recent development that may alleviate the need for short driving trips, lowering the demand for parking. Electric scooters, carts, or bikes are great for quick trips to the commissary for lunch, rather than driving half a mile.

Of course, the UFC minimums could also be changed from parking minimums to parking maximums, a practice common in Europe and recently taking hold in the United States. Some American cities are doing away with parking minimums altogether, like Buffalo, to great success. That’s not to say that no parking whatsoever will be provided – it just enables planners to right-size parking to each use, rather than cover all uses with blanket minimums.


Car dependency is a challenge for every type of planning. We need to be taking a close look at our regulations and requirements to ensure that we aren’t planning for car-centric development, and parking minimums are a great place to start. Our communities and Federal installations suffer from many negative consequences of parking minimums, and it’s time to look at how we can address them. Contact us to learn more about how The Schreifer Group can help you plan for smart, sustainable, development.

48 views0 comments


bottom of page