I only perused the article, but I didn't see where there was actual evidence that increased fuel efficiency causes increased driving, only speculation that it would do so.  This seems to be a ridiculous conclusion; who would drive more just because his or her car got better mileage?  Once we're out of high school, it's not as if we drive for fun.  The object is to get somewhere, not waste time in the car.  More importantly, because driving in the U.S. is highly subsidized, gasoline is really cheap, so increased fuel efficiency would not save that much money that someone would be inclined to drive more.

Furthermore, less fuel consumed, even by the author's calculations (10% reduction in fuel would cause a driving increase of 2-4%) would still mean less fuel consumption, which is far more important than reducing air pollution for the purpose of protecting wildlife and wilderness.  However, at these rates, the amount of air pollution would even be reduced.