The market will demand that gas mileage improve, but Obama will take credit.
Only if Obama succeeds in destroying the free market for oil based fuels.
If the world continues to search for new oil field there will be plenty of oil to fuel what ever cars the market wants.
Personally I do not believe that the general populace wants the kind of car that would be necessary to achieve that kind of fuel economy. It would need to be basically a enclosed motorcycle that does 0 to 60 mph in 12+ seconds.