parking_lotby Luke Juday

How much space does a car take up exactly?  The answer, of course, is that it depends – on the design of the place, the type of driving going on, the density, the tendency of the population to build new lanes and parking lots everywhere, etc.  The answer is important because people so frequently think of sprawl in terms of houses and house size, which is fairly unimportant until you get into really dense configurations.  It’s the automobiles that are taking up the space.

Cars are larger than houses, at least in terms of their urban footprint.

A metric every county should know about itself is its “Pavement Per Vehicle” and/or “Pavement Per Capita” (either works since there is about one car per adult in Virginia).  Most counties have the data to calculate this pretty easily. I’d love to do a state index but, unfortunately, most counties do not provide that data free of charge.

Three do, however: Charlottesville City, Albemarle County, and Richmond City.  Charlottesville and Richmond are two of the most compact cities in the state and both have lots of college students who tend to own cars but not drive them.  Their numbers should be similar and at the low end of the spectrum. Albemarle is a largely suburban and exurban county with a population density close to that of the state as a whole. It is fairly affluent, has major state and interstate highways, and should have a number at the higher end.

So here’s the question: How many square feet of pavement dedicated to automobiles — parking spaces, driveways, roads, etc., not including sidewalks or pedestrian trails — does the city or county have per vehicle?

The data on paved surface comes in all three cases from the municipalities – and props to them for making their data freely available.  Charlottesville boasts over 1,100 acres – nearly 2 square miles – of automobile pavement. Richmond clocks in with nearly ten square miles, and Albemarle has over 14 square miles altogether.  The data on number of vehicles and residents comes from the 2009 NHTS and the Census, respectively.

Remember that each house today has an average of two to three vehicles, if you’re thinking about the paved space taken up by each new home. (Note that the roads and parking spaces in the drawings are not to scale and are just meant to illustrate the approximate breakdown between road and parking lot.)


Why should we care at all about this number? Well paving places over carries a number of costs.

I. Sprawl

This issue  is too complicated to hash out in a post like this, but space is a finite commodity and large, open spaces in cities disrupt the economy of density that makes cities economic engines. Creating more auto space has a snowball effect in encouraging people to spread out more, creating the need for more lanes and more parking. If sprawl isn’t something you care about, just skip this one for now. 

II. Real cost

How much did it actually cost to lay that pavement? The answer is tough to estimate, but some back of the napkin calculations based on VDOT’s averages and some standard development numbers put it somewhere around $18,000 per vehicle for Charlottesville and $45,000 per vehicle for Albemarle County.  The lifetime of that pavement is also a thorny question – for most pavement it’s 20 to 30 years.  Annualized (without interest), we are looking at about $500/year per vehicle for Charlottesville City and $2,000/year per vehicle for Albemarle County. I think it’s actually quite a bit more thanks to the number of highways with large axle loads that require dramatically more maintenance (my numbers are based on parking lots), but we’ll go with the lower, very round figures. The pavement to drive each vehicle is costing somewhere between $500 and $2,000 a year, a number you should think about being tacked onto your other yearly maintenance and fees.  I’d love to hear a better estimate of this from someone at VDOT or a county public works department.

Who pays for this construction?  The answer is, of course, you.  But how?

Directly – in the case of private driveways, which make up a very low percentage of these numbers.

Through the cost of goods and services. Stores pay to build parking lots, those costs become part of their overhead, and are then passed onto you in the cost of the item. This accounts for about half of the pavement.

Property Tax. Local roads and other infrastructure are often maintained by the city or county, which uses property tax revenues to pay for it.

The Gas Tax. Theoretically covers major roads and highways. It represents the most direct connection between the users of the pavement and the cost of it – making it the closest thing to a user fee rather than a tax.  However…

Sales and Income Tax. In Virginia, legislators were unwilling to raise the state’s absurdly low gas tax, despite the fact that it could no longer pay for the upkeep and construction of roads. So instead… they lowered it some more! And then made up the difference with an increase in the sales tax and money from the general fund. This means people who drive less and live in more compact places directly subsidize those who drive a lot.

III. Environmental Cost

The added pavement is killing the Chesapeake Bay. It’s the only source of bay pollution that is increasing every year. Rain falls on impermeable surfaces, picks up chemicals and sediments and runs off into the bay, creating a giant dead zone in the middle where life is unable to survive.

Graphic showing how the landscape works as a green filter, removing pollution as rainwater sinks into the ground.

Up until now, this has been just another unquantifiable cost to feel bad about, but the EPA is buckling down on stormwater and making municipalities take real steps to curb it, which means these are now becoming real financial costs, funded in many places by a stormwater utility fee assessed based on the paved surface on each parcel.

Additionally, paving places over makes them ugly and often ruins them for future agricultural use. It also has implications for wildlife and other natural systems.  And it creates more air quality problems, though all of these will have to be the subjects of later posts.

Future Growth

I’ve mentioned before that the Weldon Cooper Center has us adding around 2.5 million people in the next 25 years. If that adds a proportional number of cars to places that are somewhere in between being Charlottesville and being Albemarle (say 4,000 square feet per vehicle – I bet that’s about Virginia Beach’s number), we could be looking at paving another 280 square miles of the Commonwealth.  That’s an area the size of Goochland County. Sweet dreams.

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5 responses to “Paving Paradise”

  1. Luke, This is a brilliant first crack at a really important issue. However, I think the analysis could be refined. Fundamental question: Is it fair to compare Albemarle’ vs. Charlottesvilles pavement surface per car when Albermarle numbers include an Interstate highway (I-64) and a U.S. highway (Rt. 29)? Those highways, which are used by everyone regardless of jurisdiction inflate the numbers for Albemarle. It might be interesting to see what the numbers looked like if you deducted the highway numbers.

  2. Great post – it raises interesting issues.

    According to a 2008 WaPo article by Amy Gardner, Tysons had 40 MSF of parking of all types, underground, surface and structure. 167,000 spaces.

    The comment that local property taxes pay for road maintenance is incorrect in Virginia for most counties. Real estate taxes do help subsidize transit though.

  3. DJRippert Avatar

    One inch of rain falling on one acre of pavement creates 27,156 gallons of runoff.

    In an average year, 45.22 inches of rain falls in Virginia.

    So, each acre of pavement creates 1,227,994 gallons of runoff per year. Yes, that’s right – each acre generates over a million gallons of runoff.

    As of 2010 there were 7,500,000 registered vehicles in Virginia.

    Luke says that each vehicle equates to 4,000 sq ft of pavement.

    That’s 30 billion square feet of pavement.

    There are 43,560 sq ft in an acre

    That’s 688,705 acres of pavement (1,076 sq mi)

    That’s 846 billion gallons of runoff per year

    Typical water flow of the James River near Richmond is 11,600 cu ft / sec

    There are 7.48 gal in a cu ft

    86,768 gallons of water flow past Richmond in the James River every second

    Virginia pavement creates more runoff in a year than almost 19 years worth of water flowing past Richmond in the James River creates.

    51 billion gallons of water flow into the Chesapeake Bay each day

    Virginia’s pavement runoff represents 16 days worth of water flow (from all sources) into the Chesapeake Bay

    And Ken Cuccinelli took the EPA to court when the EPA tried to force Virginia to control runoff from one source – Accotink Creek

    I guess “user pays” and accountability are just conservative buzz words.

    Note: All figures are “quick and dirty”. There could definitely be some mistakes.

  4. My head is SPINNING! First from Luke then DJ!

    Impervious surfaces are a problem but more so with older development than more recent development as the rules have tightened up considerably and are going to tighten even more AND the significant added costs from WalMart parking lots to new VDOT roads get added to what we pay for in goods and services and new road costs.

    but we need to also keep an even keel. For instance, we grow millions of cattle and poultry that .. poop… and much of it eventually finds it’s way into our streams also. In fact our own poop does because after the wastewater folks remove the liquids and treat them before they release them – the solids are carted off to be spread on fields… which drain back to the streams and rivers also.

    then we have stuff like mercury which comes from the power plants that provide us with electricity as well as coal ash which we seem to have to problem properly disposing of… etc.

    Long story short – it’s not just the car and making the car the villain is a bit simplistic.

    I’m not dismissing it nor downplaying it – just pointing out that population density has impacts… also.

    compact places with high density have much, much more impervious surfaces than ‘sprawl’ does.. on a percentage of total acreage basis and my bet is that if we calculated impervious services per capita but did not include the major interstates and other roads that it might be interesting to make comparisons.

    When I visit places like NoVa and the suburbs of Cville and Richmond, I cringe at the steep slopes that more dense housing is put on. It’s not the roads.. it’s the postage stamp front and back yards that slant at 15, 25, 30% that turn into flowing sheets of water in heavy rain events – and the streams that flow from these dense areas swell to 10 times their normal size and are full of the detritus of citified living – diapers, McDonalds stuff, pet poop, you name it…

    Next time you get curious – visit a storm pond behind a WaWa or Sheetz or office or townhouse development to get a look at one of the effects of “density”. Behind supermarkets is even more gross.. and includes shopping carts and other “hard” goods…

    where am I going with this? I guess I don’t see cars or shopping centers as the fundamental problem. They are a significant issue but so are the other things that come from people living in dense conditions.

    People use their cars… to get to doctors, hair dressers, cleaners, etc and they get their houses cleaned, appliances delivered, repaired, saved from a fire .. saved from a medical emergency because a vehicle can get to your house.

    Your food.. your furniture, your computer – your paper towels, your toilet paper, your shampoo – all comes to you on a vehicle.

    A town without roads would take us back to a medieval type existence in my view. Countries and towns with minimal roads, dirt roads, generally are not civilized.

    Our job is to deal with the realities and I think the realities are that cars are not going to go away and that our job is to mitigate the damage – to do a better job of it…

    build better storm ponds. use porous paving for shopping centers… convince people to clean up after their pets. Be prepared to pay more for beef and chicken if it means cleaning up feed lots and chicken farms.. be prepeared to pay more for electricity if we want the mercury reduced and the coal ash properly sequestered.

    but we ought not to vote against civilization.

  5. Andrew Moore Avatar
    Andrew Moore

    Thanks, Luke, for digging up the data and for the analysis, but I tend to agree with Jim – you have really raised more questions than you have answered. What is the meaningful relationship between paving and population? Is the pavement-per-vehicle measurement you cite a measure of efficiency or simply density of development? It seems to me that you would need to somehow adjust for population density to get a meaningful measure of efficiency. Or, how about simply comparing land area to paved area?

    One other comment – your piece contains the all-to-common syndrome of misleading infographic. The size of the boxes for the three jurisdictions are not proportional to the relative magnitude of the data they contain!


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