no matter what a middle aged dude tells you about carburetors, in the last 40 years, the average car's fuel economy has improved by 40%. Despite that, we're not consuming less oil.

As it turns out, we're driving longer distances, carpooling less, and there are 100 million more of us. If we really want to reduce our oil dependency, we'll need to find a new fuel source. We think that diesel and compressed natural gas are a good intermediary step before we get to a hydrogen economy.

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[via Green Car Congress