Parking vs. People

I like to mash up city data.  Sometimes it can be extremely revealing.  Sometimes it is worthless, but even then, it helps clarify what factors are or are not interdependent and interrelated when it comes to cities.  These efforts are necessary for dispelling incorrect conventional wisdom of cities.  Such as parking.  As I’ll get to.

City Observatory's Storefront Map of Dallas
City Observatory’s Storefront Map of Dallas, largely corridor driven rather than district driven.

There is no shortage of lists, rankings, and research of various data points for cities.  I find these helpful, but are generally better when you start combining some of these data points to tell a bigger, more complex story.  For example, City Observatory created the Storefront Index, which is a map and ranking of the density of storefront businesses.  This seems like a simple, straight-forward data set, but within it is couched much more revealing information:  what does it take for storefront businesses to be there in the first place?  That usually says something about street networks and population density.  Storefronts are a proxy for the more complex, emergent behavior and nature of cities.  This study is a snapshot in time of the four-dimensional nature of cities.

Similarly, Collier’s International keeps annual surveys of average monthly costs in Central Business Districts around the country.  One can intuitively surmise that the cost of parking is broadly determined by demand in relation to supply and that places with high demand likely are the most successful CBDs.  But, that is intuition.  Does data back that up?

To explore this (and to reject the notion that struggling places need more parking), I wanted to compare parking in relation to the three primary land uses of downtowns:  Shopping, Jobs, and Housing.  To do so, I created a table of CBDs using Colliers International’s parking survey, City Observatory’s Storefront Index, Job Density from the US Census OnTheMap website, as well as employed residential density within the CBD.

This table is somewhat limited to just the overlapping cities used in each study.  For example, Collier’s doesn’t have parking costs for Detroit, so Detroit doesn’t show up in any of these charts.  On the other hand, the census doesn’t have consistent data on Boston, so Boston only shows up in the Storefront vs Parking chart.  Without further ado, here is what I have assembled to date (keep an eye on the r-squared figure):


Mashing up City Observatory’s Storefront densities (ie Retail) in and around CBDs with Collier’s CBD parking costs per space.

The high cost of parking, to paraphrase the godfather, suggests (at least to the conventional wisdom) that there “isn’t enough parking.”  That is incorrect.  There is just the right amount of parking, give or take.  That parking is substituted by nearby housing and jobs.  People are nearby and therefore, those people create demand for services.  Thus, storefronts people can walk to.

As you can see, retail density as represented by storefront density rises precipitously as parking costs rise.  The best parking spot in service of retail is a nearby bedroom.  Ideally, many of them.  Like, thousands of them within walking distance, which ensures a measure of stability to those businesses, repeat business, and some protection against cannibalization from the ‘new’.

Density of jobs in various CBDs in relation to the average cost of parking per space per month.

Costs for parking rise precipitously with any increase in job density.  I can see little downside to job density as it is one of the critical drivers of transit ridership (which means you also need less parking.  It’s like there is a virtuous circle in action, or something).  Perhaps the only downside is that job density might, MIGHT, price out a large segment of the residential market since commercial rents tend to be higher than residential rents.  However, high job densities also correlate with high residential density in the same area, which usually means high value dirt, which can equal a high degree of public sector leverage in order to deliver affordable units where affordability is most needed (near jobs and transit – so those affordable units don’t have to own a car to access the local economy).

Something interesting about all of these charts is how San Francisco routinely shows up as the outlier well above the trend line, meaning they could be charging much more for parking than is currently the case.  I wonder if that is a product of their hyper-inflated residential real estate prices forcing middle and lower income people to live outside the city and drive in (since their regional transit system is woefully inadequate to their needs).

Employed CBD residents vs. 

The correlation is high for all of these factors, likely due to the virtual/vicious interdependencies involved.  The highest correlation and interestingly the most linear is the above residential density to parking costs.  This may be due to the more direct trade-off that parking is a theoretical substitute for a resident.  Instead, it is to accommodate somebody who lives somewhere else, which means somebody that could then drive anywhere else, which suggests a high degree of vulnerability to cannibalization.

And guess what?  Greater residential density equals greater storefront density:

Who needs parking when you have bedrooms and nearby wallets?
Who needs parking when you have bedrooms and nearby wallets?

Each of these demonstrates the relationship of supply and demand for space.  The most successful places, the places with the most jobs, the most storefronts, and the most working residents, have the most demand for people space.  That demand to be there outstrips the supply of parking space, driving costs for parking up.  Since parking is strictly a cost in service of productive real estate, successful areas can spend less on the construction of new supply of parking, which can lead to either more profitable investment or more affordability.

Space for parking is unproductive real estate.  It is space wasted in service of other productive real estate.  As it serves other real estate land uses, the conventional wisdom always suggests, “give us parking, so we can get X, Y, or Z land use.”  However, that provision of parking is often at the expense of those same X, Y, and Z land uses as well as the stability and predictability of success for those land uses.

Like all things there are costs and benefits, not all of which are quantifiable.  And for the most part, when it comes to parking in CBDs or any other place you want to be 1) urban, 2) resilient, and 3) valuable, those costs end up outweighing their benefits, which is precisely why you want high parking costs in order to offset all of the negative externalities.  The space is simply worth more as productive space than as a warehouse for cars if you can construct the full ecology of successful, vibrant urban places that not only function, but succeed via less parking.

Therefore, if the productive real estate can be productive without the parking, having the parking is inherently inefficient and the goal should be to maximize efficiency and productivity of real estate.  I’m not saying have zero parking.  Instead, what any CBD should be incorporating into their revitalization strategy is to systematically reduce the ratio of parking to productive land uses like retail, jobs, and housing.

What I am saying is the supply of more parking is rarely, if ever, the correct solution.  And, whatever parking there is should have minimal negative impact on the street nor the surrounding properties.  For example, on-street parking can help protect pedestrians from moving cars, can help calm traffic, and serves ground floor retail.  If you could quantify all of those factors, on-street parking would in all likelihood have a net positive impact.  However, you also want it to be priced high enough that the market will bear because that is the sign of success.  The goal isn’t to price it high, but instead have an area in such high demand that people are willing to pay enough to offset the negative costs of arriving to that place by private vehicle.




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