Parking planning

December 2013 » Features » PROGRESSIVE ENGINEERING
Careful consideration of specific patterns and needs can help restore communities' traditional appeal.
Carolyn Krasnow, Ph.D.

The dominance of the automobile in the post-war era changed the way most cities function. As car traffic overtook foot traffic and sprawl challenged old notions of "going to town," many downtown neighborhoods ceased to be the focal point of their communities.

In response, many municipal leaders and planners are trying to return to classic planning approaches to transform their communities into more livable and interesting places. These approaches – often lumped together as "smart growth" – aim to create environments that are less dominated by the requirements of automobiles and more focused on walkability and multi-modal access to support the kinds of mixed-use, stroll-able downtowns that were the norm before the rise of suburban strip malls.

While the benefits of promoting greater balance between vehicles, pedestrian traffic, bicycles, and transit are obvious, it is forcing many municipal officials and planners to rethink the relative roles of cars and parking downtown. Further complicating the situation is the fact that many communities continue to struggle to compete for downtown businesses and shoppers with suburban malls and office parks that offer free and plentiful parking. For a long time (and even now) many cities tried to compete by implementing minimum parking requirements for new development while, at the same time, lowering parking rates at on-street meters or removing them altogether. The legacy is city codes and policies that encourage driving, even from place to place within a small radius, and fuel the need for more resources to be devoted to parking.

To help support smart growth and their own financial performance, many cities can better meet their parking needs simply by managing existing parking through pricing and enforcement, while at the same time encouraging greener transportation modes and more people-friendly streets. But there are limits, and while some of the more ardent proponents of walkable streets take the approach that parking and cars should be discouraged as much as possible, they may be trying to achieve too much change too quickly; most people do rely on cars and downtowns don't function if people can't get there.

Ultimately, cities must strive to achieve balance between urban design, economics, aesthetics, real estate markets, environmental concerns, and public perception. Parking requires careful consideration of the specific patterns and unique needs of the area in question, and there are no one-size-fits-all solutions.

Where cities often stumble
One of the primary problems facing cities is that they approach parking planning as a traffic engineering issue rather than an element of urban planning. As such, they tend to rely too heavily on quantitative models that can only tell part of the downtown parking story.

The Institute of Transportation Engineers' landmark compilation, Parking Generation, provides important statistical data on how much parking a given land use will generate, but the data were deliberately collected for stand-alone land uses and mostly in low-transit areas to understand parking in an unconstrained (absolute peak) situation. The parking generation ratios it provides are helpful for understanding peak potential demand for a given land use, but are really a starting point more than an answer.

The Urban Land Institute's Shared Parking manual extended the work to account for mixed-use settings where the interaction between land uses that have different peaks (e.g., offices and cinemas) can reduce overall parking needs, and provides a method for modeling the reductions. This adds much-needed nuance to the planning of anticipated build-outs in mixed-use areas and is a more valuable tool for downtown or other mixed-use environments.

Even so, the typical downtown presents a much more complex picture than can be addressed through quantitative modeling. In fact, parking planning is as much about consumer choice as it is about car counts.

For example, it's not uncommon for stakeholders to think that their parking system is always full when in fact there is plenty of capacity within a few blocks of the core. The shortage of spaces turns out to be a shortage of spaces right where people want them – in front of the stores they want to patronize or the businesses where they work.

The trick to meeting this parking need isn't typically to create more parking right in that small core – it's often not possible in a built-out area anyway – but to adjust policies and rates in a way that will help spread the parking demand out across resources. Some parkers will be willing to pay a premium to park near the front door of their destination, while others will be willing to walk a few blocks for less expensive (or free) parking.

The questions, "Do we have a parking shortage?" and "How much parking do we need?" can't be answered with a code calculation, or statistics from a manual, or even a shared parking model. How much you need depends on the radius you're willing to consider as available resources, and how much you're willing to charge to make use of that radius.

The best parking planning begins with a quantification of potential new demand through a shared parking model but then looks closely at the specifics of the locale to make the most effective use of available resources and/or alternative modes. History is replete with examples of small communities that built parking garages at great (often financially debilitating) expense to meet anticipated need only to see the spaces in those new structures go largely unused. Maybe the parking was overbuilt, or maybe it wasn't convenient enough, or maybe it was as expensive as the curb parking that most people prefer and they continued to cause congestion looking for the perfect spot right outside their favorite restaurant. The planning is as much about psychology and management as parking generation rates.

These communities would have benefited from parking studies that looked not only at current and anticipated need, but also at how parking resources could be reorganized to more effectively utilize existing supply to support both current need and future growth, while at the same time incentivizing transit-oriented development through shared parking arrangements. By pursuing this approach, cities and towns can often meet their parking needs and encourage new residential and business development without raiding municipal coffers and without turning attractive downtown areas into parking lots. It's important to know the limits, though: There are already instances of developments being planned with such optimism about shared use and walkability that they have insufficient parking to meet customers' needs. Careful evaluation is needed more than dogma.

Good news
The good news for cities and towns is that minor changes to the economics of a community's parking system can often help address parking demand while saving millions of dollars by avoiding new parking construction. But for many cities and towns, this approach requires a completely different way of looking at parking, moving toward a more qualitative analysis.

To work, city planners and engineers have to become more comfortable with different approaches than they may have been used to in the past. How much surplus is realistically usable to support overflow demand before new supplies are needed? How far are people willing to walk to get cheaper, all-day parking? What kind of rate differential will work to create premium parking in the core and attractive discount parking a few blocks away? Do policies support a "park once" usage pattern or is traffic exacerbated by people getting back in their cars to go one block to another store? How much less parking can be built to support growth of alternative modes of travel without rendering office, residential, or retail space unleasable? These aren't questions that can be answered solely through car counts and other quantitative approaches.

And the answers will vary from town to town or from city to city. Attitudes about walking distances, acceptable parking rates, alternatives to the automobile, and all the other factors that affect parking policy and urban planning can differ radically within a span of a few miles. Just as many cities erred in trying to apply suburban models to downtowns, now we see people assuming that the same principles that worked so beautifully to create a vibrant destination out of a derelict neighborhood in Pasadena translate to every situation.

There are no textbook answers. There are many angles to consider, but studying the details of how your system really operates day-to-day is vital to creating the conditions for successful implementation of smart growth. Even in the absence of growth plans, any town or city can benefit from the improved efficiency that comes from careful parking planning and management. If citizens are complaining that parking is a nightmare, it may be time for leaders and planners to look for opportunities to spread demand out before investing in a garage or even a surface lot.

"Many of America's cities are moving back in time, at least when it comes to urban planning."

Many of America's cities are moving back in time, at least when it comes to urban planning. By approaching parking planning in a more qualitative fashion that takes better advantage of existing parking resources, city leaders and planners can use parking to help create more walkable, diverse, and livable communities.

Carolyn Krasnow, Ph.D., is a vice president with Walker Parking Consultants and the managing principal of the firm's New York office. She can be contacted at

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