De-asphalting

Our efforts to create convenient parking for automobiles have, paradoxically, made access to businesses and services more difficult.  Highway commercial centers and arterial corridors require enormous parking areas because there is almost no way for people to walk or bike to them safely.

Local planning and zoning ordinances set minimum parking standards.  Standards for parking at retail shops are as high as 1 space per 200 square feet of gross space, and for restaurants, 1 space per 4 seats, plus parking for employees.

Requiring all buildings to provide ample parking is a bad policy.  Ordinances often require more space for car storage than space for people. One example: a church might be required to provide 1 space per 5 seats, and if each seat occupies 20 SF, this effectively requires 1 parking space per 100 square feet of building area.  One parking space equals 300 square feet (driveway, aisle, and parking) at the highest design efficiency, thus tripling the building footprint on the site.

Minimum parking requirements lock up useful land, contribute to sprawl, and cause stormwater problems due to impermeable materials.  Parking requirements prevent infill development on small lots, and also prevent new uses for existing buildings that need to adapt to remain viable.  Parking minimums can deter developers from investing in urban projects, because the cost to provide parking can be high – as high as $30,000 per space in one recent project in our city.  If cities remove minimum parking standards, businesses will be free to provide as much parking as they need, and as much as their customers demand. 

Larger community benefits accrue from removing parking minimums.  Adding 300 square feet of green space, instead of 300 square feet for one parking space, improves property values, improves stormwater efficiency and reduces flooding, improves air quality, reduces the heat island effect and improves energy efficiency for buildings nearby, and reduces CO2 emissions.  Planting trees, even on that tiny plot of ground, can boost these environmental benefits.

Getting businesses to demolish asphalt and replace it with greenspace and permeable site cover comes at a cost: about $5 per square foot to demolish and haul away asphalt, add 12” of topsoil, grade, and seed with wildflowers or other native groundcover.  The payback for these improvements is about 2 years… but the green space will continue to pay dividends in improvements in property values and the rest, and trees will continue to sequester more carbon and take up more stormwater over time, rather than degrade and lose value, as asphalt does.  Asphalt requires a new overlay every 7-10 years, and a new base course and asphalt every 15-20 years (interestingly, where asphalt is shadowed by trees, it lasts longer).

Allowing green space at the time of the initial development, in lieu of parking, is more cost-effective than converting it later, and offers immediate benefits to neighboring businesses.  The worst thing that might happen with less parking on site, is that shoppers have to explore the city as they walk between their parking space and their destination – often resulting in additional sales for the intervening shops.

Resources:

Donald Shoup, The High Cost of Free Parking: http://www.shoupdogg.com/publications/

National Tree Benefit Calculator: http://www.treebenefits.com/calculator/

National Stormwater Calculator: http://www.epa.gov/water-research/national-stormwater-calculator