dinosaurFor twenty years, these gas-guzzling beasts roamed the earth, devouring petroleum reserves and hogging parking spaces.

Yesterday, the equivalent of a meteor crashed down on the dinosaur SUVs. Higher national fuel efficiency standards announced by the Obama administration means the end of the SUV era.

The higher mileage and emissions standards will take effect in 2012, but they already are transforming the American car and truck fleet. The new rules will require all new cars and trucks sold in the United States to achieve an average of 35.5 miles per gallon (mpg), about 10 mpg more than today’s standards. Passenger cars will be required to get 39 mpg, and light trucks 30 mpg. Cars and trucks on American roads will have to become smaller, lighter, and more efficient.

It was American automakers who invented the SUV. While Japan was developing hybrid technology in the 1990s, Detroit was rolling out 50 million Ford Explorers a week. For awhile, it worked. But the Big Four leaned almost exclusively on the SUV to carry them into the 21st Century. Even as oil prices skyrocketed, the economy imploded, and global warming became an international buzzword, American automakers continued pushing the SUV and lobbying against stronger fuel efficieny standards.

So is anyone really surprised to see the American auto industry go belly-up?

The SUV will linger for awhile; those behemoths in the back of the lot still have a lot of miles left in them. But the new fuel efficiency laws make one thing certain: the big, pointless, overpriced SUV is rumbling slowly into the sunset.

And ultimately, that’s a good thing–even for the thousands of laid-off autoworkers who will eventually be producing a smaller, lighter, more economical American auto fleet. Higher fuel efficiency standards means we can all breathe easier. Better fuel economy has a direct impact on rates of heart disease, lung disease, asthma, strokes, and a host of other killers exacerbated by highway-spewed pollution. Better fuel efficiency also saves thousands of dollars at the pump (the Obama administration estimates $2,800 per year for every household), reduces our foreign oil dependence, and puts us on the road toward a more sustainble long-term energy future. The transition will be bumpy, for sure, but the best way to avoid the fate of the dinosaurs–and the SUV–is an efficient auto fleet powered by more renewable forms of energy.