From the Christian Science Monitor, evidence that consumers are beginning to think about gas prices as they make new vehicle purchases:

Last month, 49 percent of new-car buyers, the highest level ever, had changed their mind or were thinking strongly about buying a vehicle they would not have considered because of gas prices, according to a survey by Harris Interactive and Kelley Blue Book.

Over the short term, rising gas prices only affect consumption a little bit, because people have only so much flexibility to change their driving habits.  Over the long term, though, people start making more fundamental changes—where they live, what they drive—that can lead to more significant reductions in how much gas they use.

There’s still plenty of room for skepticism.  Sales of hybrids are surging now, but some industry analysts are predicting that demand will top out, with hybrids commanding a small share of the market.  (Some of those skeptics, of course, are from car companies that don’t produce hybrids—so take those predictions for what they’re worth.)  But then there’s this:

Even McManus – the hybrid cynic-turned-believer – has serious doubts about how big an impact even a massive surge in hybrid sales will have on reducing America’s oil dependence. His analysis, for instance, shows a "rebound effect." For every 1 percent decline in the cost of fuel, Americans drive 1.85 percent more.

That number seems way too high to me, and this lit. review by Todd Litman of the Victoria Transport Policy Institute seems to agree.  Still, all else being equal, increased vehicle fuel efficiency does tend to reduce the cost of driving a mile, which in turn increases the number of miles people drive.  Which leads to this seeming paradox:  in a world of hybrids, we might drive more, but still use less gas.

In other hope-inspiring vehicle news, cleaner diesel vehicles may be on their way.