Purdue University researchers surveyed the total land area devoted to parking in Purdue's home county, Tippecanoe, and found that parking spaces outnumber resident drivers 3-to-1 and resident families 11-to-1. The total parking area is larger than 1,000 football fields.
"Even I was surprised by these numbers," says Bryan Pijanowski, associate professor of forestry and natural resources, who led the study. "I can't help but wonder: Do we need this much parking space?"
Pijanowski says that his results, which he considers underestimates, are a concern, in part, because parking lots present significant environmental problems.
They are a major source of water pollution, he says, because contaminants collect on parking lots' impervious surfaces and are then easily carried away by rain into rivers and lakes. A special computer model calculated that Tippecanoe's lots turn out about 1,000 pounds of heavy metal run-off annually, says Bernard Engel, professor and head of the Department of Agricultural and Biological Engineering. Heavy metals accumulate on lots from car batteries and are even deposited by airborne fumes.
Parking lots also help add to the "urban heat island effect," which can raise local temperatures 2 to 3 degrees, says Indiana state climatologist Dev Niyogi. "Urban areas have a higher capacity to absorb radiation from the sun than surrounding areas, and these areas become warmer."
In the future, more efficient development planning and shared or multiple uses of parking lots could benefit businesses and individuals, Pijanoswki says. "People can help by first realizing that our land is not unlimited and that we need to use it prudently."