The Perils of Parking Lots

1 October 2007

Parking Lot

A recent study undertaken by a researcher at Purdue University has found that in one Midwestern county, parking spaces outnumber residents three to one. Using software based upon aerial photographs, researcher Bryan Pijanowski has discovered that parking spaces are taking over Tippecanoe County in Indiana. This study has important environmental ramifications that connect to pollution, land use, and even global warming.

Even at Carleton, there is a lot of land dedicated to parking. Last year, on a Friday during convocation, student volunteers counted 588 vehicles on campus, roughly one car for every three students on campus. Furthermore, last year there were 455 student permits issued, along with 1,178 faculty/staff permits.

Parking stress has been a critical issue on campus and the demand for more parking spaces does not come without its costs. You wouldn’t think it when you look at them, but parking lots are hotspots of environmental degradation. Certainly, on a most basic level, parking lots mean less space for plants and animals to inhabit, but the environmental impacts of parking go much deeper.

Parking lots are a tremendous source of runoff and pose a threat to bodies of water. The amount, speed, temperature, and quality of the water that flows from parking lots after rains are a major concern to the EPA and many other environmental groups. Located on the banks of the Cannon River, Carleton has been particularly cautious with its design of parking lots, installing vegetated swales and drainage ponds to hold and filter storm water from lots those adjacent to the Recreation Center. The parking lot at the Arboretum office is a pervious surface that uses metal cylinders to help draw the water into the ground, rather than down the hillside (and eventually into the river). To see where all of these features are on campus, check out the Campus Sustainability Map.

The second major environmental impact of parking lots is perhaps more symbolic. Excessive parking spaces are one of the most telltale signs of suburban, automobile-based sprawl. Since residential zones are increasingly separated from commercial areas by long, unwalkable or unbikable distances, driving is becoming a more of a necessity to get from place to place. The need for extra spaces adds up: if the results from Pijanowski’s study in Tippecanoe County are typical of the entire United States, the land use would result in more than 6,000 square miles of parking lots, an area larger than Connecticut. Imagine the potential land uses for an area this size. Are usually-vacant squares of pavement really the choice we want to make?

The final reason parking lots are environmentally harmful lies in their connection to global warming, albeit indirect. Parking lots are significant contributors to a phenomenon known as the urban heat island effect, in which artificial surfaces retain the sun’s energy in a way that trees and vegetation do not. The Intergovernmental Panel on Climate Change (IPCC) has determined that urban heat islands will increase the impacts of global warming in urban areas, which will likely lead to more heat-related deaths. One of the major impetuses for green roofs is to counteract these urban heat islands (provide link). Replacing permeable, vegetated surfaces with impermeable parking lots further adds to problems associated with microclimates and global warming.

So, what can be done? One possible solution for the national problem is to seek an end to free parking. While unpopular, this is not a new idea. For years, tolls and parking fees have been used around the world in attempts to curb driving. Examples of these policies are everywhere. Carleton, for instance, charges students $50 annual registration fees to have a car on campus. The city of London garnered headlines when it introduced a congestion pricing plan for drivers who enter the city’s downtown business district between 7am and 6:30pm during the week.

At Carleton, one initiative currently being explored by the Environmental Advisory Committee is the possibility of teaming up with a car-sharing program, which would reduce the need for individual vehicles on campus, and with it, the need for parking space. Another idea that has been discussed in the past is making carpooling and the use of public transportation a more attractive option for faculty and staff who commute to Northfield from the twin cities.