We don’t need new technology to save us, just a little ingenuity.
After a few minor tweaks, Ernie Rogers can get up to 76 mpg in his 2003 VW diesel Beetle:
He drove 1375 miles…[on] just 18 gallons of fuel– 1200 miles of which was accomplished on just one tankfull (15.5 gallons). His trip fuel economy was 76 miles per gallon. Rogers’ car included several small refinements that added up to the exceptional mileage: a drag reducing device he designed and built himself (pictures [here]), lower-rolling-resistance tires, low-friction engine oil, and use of a B5 biodiesel blend fuel to increase efficiency and improve emissions.