So you'd be satisfied with approaching the 'existential problem' of climate change with a handful of billions in R&D? If so then fine have at. And here the rest of us were all thinking you were serious with all your completely harebrained ideas like carbon taxes and such.
You realize that fuel economy standards calculated by CAFE standards aren't the same as the window sticker MPG? And plus CAFE calculation methods have changed, not to mention that fleet standards are a function of the vehicle size mix so domestic makers are actually further incentivized to build
even more SUVs and trucks than they do now. So I guess climate change is tolerable to the politicians when they want to benefit a specific group like UAW employees at the expense of others.
We probably ought to go for the tried and true cap and trade. I know you don't feel that bringing market forces to bear on the problem will work because Al Gore is a wizard but it's historically worked.
You do realize that Subyman and I were speaking from direct experience with our own vehicles.
My 04 Suburban 5.3 V8 295 hp

was rated at 14-18 mpg and averaged about 14.8 for us. Our new 15 Suburban 5.3 V8 355hp is rated at 16-23 mph and is averaging about 19.5 for us. (50 mile peaks as high as 24.5mpg)
That's a 30% increase in real mileage and a real impact of Federal CAFE standards.
Now the state and local govt here has fucked us. Thanks to their school budgeting no one within 2 miles of an elementary school gets bussed. Children 2nd grade and younger may not walk home. For middle school my kids who go to magnate schools only get bussed home.
So the net result is my wife and I used to be able to carpool in our sedan with everyone in the morning and the Suburban went 3 -4 weeks between fill ups. Now we take seperate cars and 500 parents decend on the school twice a day and idle for 30 minutes. But hey we saved tax dollars somehow by not busing at the cost of gas, time, pollution and traffic.