I think it's a bit overstated. Everyone talks about increase CAFE regs, but it seems like they miss the point a bit: it stands for Corporate Average Fuel Economy... so, if they raise it to 35MPG for 2020, that doesn't mean every vehicle in the fleet has to get that number--it means the average fuel economy of all the vehicles sold (and I'm not talking averaging the models here, I'm talking total production) has to equal 35MPG. So, trucks can still get 17MPG, so long as they sell an equal number of vehicles elsewhere in the model lineup that get an EPA rating of 53MPG. No, it's not easy, but it's easier than building a 35MPG ¾-ton truck.
What I wonder is why none of the major automakers seem to be courting the idea of a diesel hybrid. Trains have been this way for years; around town a small diesel engine could run at a steady RPM to power a generator that would create electricity for traction motors at the wheels; if the need becomes more than the steady-state power generation can handle, a computer increases the RPM of the diesel to push more juice out of the generator and meet demand for acceleration and passing duties. As demand decreases, the diesel engine slows down.
Diesels are naturally efficient engines, and with new techonologies like Mercedes-Benz urea-based Bluetec system, they can be made to run very, very cleanly... particularly when run on organic fuels such as biodiesel, used cooking oil, or any number of things on which they'll operate.
Something must be done, whatever it is... still, I think the dependence on oil is a larger problem than environmental impact. Today's cars run so cleanly that it's hard to believe the greenies are still screaming. A Viper has to pass the same emissions as a Honda Fit, and creates 600HP while doing it... and getting better fuel economy than the far-less-powerful V8 beaters I drove for so many years.
Pity the carmakers: federal regulations for emissions and safety have added so much weight to vehicles that the average car now weighs something like 400lbs more than the average car 25 years ago, despite advances in weight-saving materials like plastic, aluminum, and composites... and now, with all the crap we never wanted in the first place, they're expected to make these heavier cars easier on a gallon of fuel. Tough gig... I don't have the answer, and frankly, I'm glad it's not my job to work one out.
