Ages ago -- 1992? 1993? -- when I was writing about air pollution and automobiles and California standards and all that, I interviewed a few people who told me that the best thing the government could do to reduce pollution from automobiles would be to buy old cars and get them off the road.
Amazingly enough, they're doing it
. Unfortunately my 1997 Subaru, which gets 23 miles per gallon, doesn't qualify.