Detroit will be motivated to do this when they can do it for a price people are willing to pay. Car manufacturers, all else being equal--an important caveat--have every reason to make their cars get mileage as high as possible. If two SUVs have equivalent prices and features, and one gets better mileage, everyone will buy that one.

The manufacturers have apparently decided that, for now, the technology required either is too expensive, not reliable, or needs a lot more work to implement. Probably a combination of all three. Naturally environmentalists assume they know more about the ins and outs of building cars than the carmakers do, and are convinced that the only reason that 40 mpg SUVs aren't on the road right now is because carmakers are basically evil, and probably secretly in cahoots with the oil companies. All that is needed to get Magic Cars into the showroom is to have the government force the companies to build them.

CAFE standards are like the minimum wage. It's easy to set an arbitrary number, then stand back and ignore the inevitable consequences (weaker auto frames, high prices, etc.) Why not just cut the crap and demand 100 MPG?

I'm fascinated by the number of people who bitch about cars using too much gas and when asked why they don't drive an electric, look at you like you're nuts and say "you know how MUCH they cost?"

BTW, when an ethanol production facility delivers more energy than it uses, let me know.