Don't Worry, Green Cars Don't Really Mean More Driving

From Mother Nature Network's Jim Motavalli:

Here’s the good news: According to the wonks at the University of Michigan’s Transportation Research Institute, the average car sold in March was 25.4 mpg, a new record. In truth, fuel economy has been improving all year — it’s up 0.4 percent since January.

Aha, you say, the sunny skies will yield to clouds — if people get better fuel economy (or even buy electric cars), they’ll drive more. It’s human nature; people travel more when it’s less painful to them.

David Owen wrote about this in the New Yorker. Give people Energy Star air-conditioners and they’ll just turn them on more. Owen calls it the Jevons Paradox: "This effect is usually referred to as ‘rebound’ — or, in cases where increased consumption more than cancels out any energy savings, as ‘backfire,’” he wrote.

But Matt Mattila of the Rocky Mountain Institute denies that factor is at work with drivers because most don’t even know their fuel economy. And even if they did, they’re unlikely to take advantage of it by covering more miles. You might be better off saying that because Americans are heavier, they're hurting fuel economy gains. (That one's true.)

The University of California Transportation Center says it measured this “rebound effect” back in 2007 and discovered “that it is not large. Moreover, we find that it has become smaller over time, and is likely to become smaller still. This means that improved fuel efficiency does translate into lower fuel consumption.”

And guess what? Actual vehicle miles traveled (VMT) and fuel consumed continues to fall, despite population growth and the supposed backlash everybody’s worried about. The absolute amount of fuel consumed by American cars and trucks fell 11 percent between 2004 (when fuel use hit a peak) and the end of 2012.

Americans are driving less and using less fuel. The rates for 2012 distance driven roughly mirror the mid-1990s, and the fuel consumed is lower than in 1984 (when the University of Michigan’s figures begin).

Michigan’s Michael Sivak admits there’s some truth to the rebound effect: “Having more efficient vehicles will lead to an increase in driving,” he said. “But the general consensus is that only about 10 percent of the gain in fuel economy is effectively lost due to an increase in driving. In other words, 90 percent of the gain in fuel economy is retained — not compensated for by increased driving.”

So go ahead and buy that Prius or Nissan Leaf. Here are some great choices for fuel-efficient used cars. You’re not likely to drive it much more than your current car.