When I was a kid, gas was 18 cents a gallon and my mom bought 'a dollar's worth of regular' at a time. At that time, 12 MPG was considered really good. Auto manufactures have consistantly made more efficient cars, but whenever gas gets cheap Americans flock to larger more powerful engines and larger frame vehicles. We have gone through this cycle several times now. In the 1960s we wanted muscle cars. Then came the gas embargo, and large cars were junked and we bought smaller more efficient cars. Then with inflation figured in, gas got cheaper again in the 1990s, and we bought SUVs and larger PU trucks with big engines and lots of power. I have an early model Toyota Tundra and that was considered under-powered for a V8. I think it has pleanty of power and it gets reasonable mileage (used to anyway, with pure gas it got 18 MPG on the highway, now its 17 MPG with E-10). But they have since come out with a bigger engine and bigger frame Tundra to please the American PU truck crowd with worse mileage. And now gas is spendy again... So we are (again) building smaller commuter cars, like the Smart, Fiat 500s, and lots of hybrids. 30 to 50+ MPG vehicles. As long as gas remains expensive, we will buy these vehicles and demand will push more and better mileage cars into being produced. But... if gas drops in price again, as it is likely to do, we will again start to drift toward larger cars with more power and less efficient vehicles. Human nature. Humans are naturally rather inefficient creatures. We are more interesed in instant gratification, staus and overkill than economy, altruism and long range goals.