California is one of nearly a dozen states that fought the Bush administration for stricter guidelines. Governor Arnold Schwarzenegger applauded the move and hopes all 50 states buy in.
California new car dealers agree a single national standard would be best for the auto industry and say buyers should be prepared to pay more. Dealers estimate the price of a new larger vehicle could go up by as much as $8,000, in order to comply with the tougher emissions standards.
And now the multi-billion dollar question -- what can we expect of those cars? It is likely they will run on a variety of technologies including hydrogen, biofuels, gasoline, and electricity. However, the conversion will not happen quickly or easily.
It's hard to imagine how your automotive future might be in a filing cabinet, but Dr. Marshall Miller of UC Davis has already replaced the concept of "if" with "when."
"All of these are energy storage devices," is how Dr. MIller describes various batteries and capacitors. Experimental, for now, as Dr. Miller and his partners look to advance plug-in, electric hybrid cars.
"Every vehicle in the future will end up being a hybrid. They will have energy storage systems like batteries on board," said Dr. Miller.
A plug-in converted Prius, for instance, goes 20 miles without using a drop of gas. However, the conversion will cost $10,000, and the average American driver still cares more about horsepower than carbon neutrality.
Dahlia Garas also works at UC Davis and sees a vicious cycle needing to be broken.
"The blame maybe goes both ways. The consumers demand it and the car manufacturers have to build what people will buy," said Garas.
Even with cleaner, more efficient cars, it will take years to see a change in the environment. The problem is it's a numbers game. There are a quarter of a billion cars on American roads. The average car spends 14 years between the factory and the scrap heap.
"In about 10 years, we'll see most of the cars, most of the miles driven on the road will be by more efficient cars," said Dr. David Greene, who specializes in transportation energy.
But getting there will not be easy. Dr. Greene notes that automakers move slowly. They lock their designs two years in advance, and now the EPA wants them to make cleaner cars with stricter guidelines.
"I think the problem right now is... whether they can afford anything," said Dr. Greene.
Just as important, can they make those cars affordable in tough times when consumers seem unable or unwilling to buy just about anything.