Yesterday, Matt pointed to a Times article saying that new hybrid technologies were being pumped into the acceleration side of things rather than going to increase fuel efficiency. That's not going on everywhere, sure, but the Accord hybrid and a few others are using the increased power to, well, increase power. This is essentially what happened in the 80's when the advances that had been going to cut fuel consumption were, with Reagan's freeze on CAFTA standards, plowed into engine muscle, at least by American companies. The Japanese kept going for efficiency and, well, you know how that turned out.
Matt uses this as evidence for why we should let the market take care of oil or, if we insist on meddling, have something straight forward like a gas tax. I'm not so sure. As I've said in the past, gas taxes are enormously regressive, hurt those who (for reasons of employment or whatever) can't change their transportation patterns, and will make all manner of good more expensive because they cost more to move and produce, making it double regressive. And this is all in the platonic land where we could actually pass a gas tax.
What the study does show is that subsidies for hybrid purchases are no longer a good idea. So let's not have them. Don't subsidize hybrids. Subsidize fuel efficiency. 30mpg and over gets a small subsidy, 40 gets a larger one, 50 nets you even more cash, and 60 makes you rich. Because, in the end, what we want isn't technology itself, but better fuel efficiency. And we can incentivize that directly.