Hybrid diesel - It worked for the U-boat.
One obvious, yet totally ignored solution! Or how about just plain diesel. Many cars sold in the US have brilliantly engineered, computer controlled, clean-running, small turbo-diesel counterparts on sale in the rest of the world that achieve 2-3 times the fuel mileage, with no loss in "performance,*" while meeting EU emission standards which mimic California's. That FIAT 500 gets 70 mpg with diesel power in Europe. Lucky to break 30mpg here in the US! Ditto, the VW TDI.
If the American car passenger fleet were diesel powered, fleet mileage could more than double and there would be NO NEED for fuel importation.
Somebody in government was frightened in utero by a smoky old MB 190 D, and we are doomed to suffer ever since? Perhaps if we had a POTUS who could actually change a tire or check his own oil?
*in re "performance:" WTF says a humble Honda Civic has to have better 1/4 mile times than a 1975 Ferrari? This is a country with speed limits which rarely top 70mph on the interstates ... and with stop lights every 500 yards everywhere else? As a car buyer, would you trade 2 seconds more "0-60" in exchange for another 20 mpg?
More on the idiotic "stoplight" policy later. Many are completely unnecessary, many others could easily be replaced by my favorite: the round-about, which has the added advantage of killing off more inept drivers.
It worked for Volkswagen, in Germany, in 2008. I think it got 79MPG.