New York Times, April 20, by Stephen J. Dubner and Steven D. Levitt
http://www.nytimes.com/2008/04/20/magazine/20wwln-freakonomics-t.html?_r=1&oref=slogin
“I was a graduate student at Stanford,” he says, “and I drove maybe 2,000 miles a year. But I paid roughly the same $1,000 as if I’d driven 10 times as much, which was a huge portion of my budget.”