In gradeschool in Long Beach, CA a teacher told my class that "By 1990 (or was it 2000?), it will be illegal to drive a car that burns gasoline in the state of California." That was circa 1968. A reasonable presumption back then. After all, we'd put men in space in a lot less than 28 years and 2H2 + 02 => 2H20 gave you a lot of bang for the buck. Doubtless she thought that'd be harnessed for automobiles well by now. Ah, the long past age of optimism...