A point of clarification about CAFE standards, apropos of Dave’s post below.
According to this report (careful, it’s a pdf) from the Victoria Transport Policy Institute, increasing CAFE standards would, in fact, save fuel (contrary to the claims of this this moronic article). The problem is that more fuel-efficient cars are also cheaper to drive. And that would mean that CAFE standards, even as they save fuel, would also slightly increase the number of miles people drive.
Now, driving obviously has all sorts of “externalities” — costs that are borne by someone other than the driver. Some of the externalities are related to fuel consumption and the resultant air emissions; CAFE standards do help reduce those problems. But extra driving also means more car crashes, more congestion, more noise pollution, more risks for walkers and bikers, higher rates of obesity, lower rates of physical activity, more expenses for road building and maintenance, and so on.
So in simple terms, all the bad stuff that comes along with extra driving would overwhelm the good stuff that comes from consuming less fuel. Yes, we’d import a bit less oil, but we’d get in more crashes, build more roads, sprawl a little more, etc. And the human and environmental costs of all those other things (according to the VTPI report, at least) outweigh the good that’s done by raising CAFE standards.
I don’t think that’s reason not to have CAFE standards. But it is reason to be very careful about what other policies you have in place that would help soften those unintended consequences.