"The real problem is, though, cars don't move people, cars move cars."
"Even if we were able to produce a 100 mpg, zero pollution vehicles, we'd still need to maintain the infrastructure of roads, bridges, and energy distribution. That means steel, concrete, asphalt and plastics. Just concrete production alone generates as much as 10 percent of all greenhouse gas.
And there's another intractable problem: the very thing that makes tires so useful – comfort, stability, adhesion – also produces immense rolling friction. One reason trains are able to transport people using far less energy per passenger mile is that there are fewer wheels per person and steel wheels have much less rolling friction.
But there's an even more profound problem with building more efficient cars. In 1865, English economist William Stanley Jevons discovered an efficiency paradox: the more efficient you make machines, the more energy they use. Why? Because the more efficient they are, the better they are, the cheaper they are and more people buy them, and the more they'll use them."
Thanks to John Hartz