"We all pay for it, not in our role as drivers, but as residents, taxpayers, and customers," says Shoup, who documents the phenomenon in his book "The High Cost of Free Parking." Big parking lots hike building costs and get passed through to the consumer, sometimes through higher rents in their apartment buildings or bigger costs at their grocery stores. "Every place we drive and park free, we really pay for that parking as something other than as a driver," he says.
Others worry about the environmental impact of all that paving.
"We've had a big interest in this area for a while now, but it's not been well studied," says an official with the US Environmental Protection Agency (EPA) who requested anonymity because he did not have permission to speak to the press. "It's the amount of water, the speed and temperature of it pouring off these oceans of asphalt we have in this country, that concern us. And that's not even talking about the contamination washing off all that asphalt."
Early indications point to a lot of asphalt out there. If a single parking space averages 9-feet by 19-feet, then Tippecanoe County's 355,000 spaces translates into two square miles of pavement, the equivalent of about 1,000 football fields. If Tippecanoe is typical, that would mean the US has paved over roughly 6,000 square miles – an area larger than the state of Connecticut – to accommodate cars or trucks.
That's a conservative estimate, Pijanowski stresses, since he has not yet included on-street and residential parking or any other floors of parking garages except the rooftops, which are visible by air. In a nation with nearly 250 million registered vehicles, a few extra Rhode Islands of concrete might not seem to matter that much.
But a key finding in Pijanowski's research is the ratio of parking spaces to vehicles. In Tippecanoe County, at least, there are three times as many spaces as registered passenger vehicles. And there are 11 times as many spaces as families, his yet-to-be-published study found.