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With a laptop tracking power and gas consumption and CO2 emissions,'s four plug-in Priuses serve as a test fleet for the charity's $10 million plug-in electric hybrid vehicle research program. And according to the stats, they're already outperforming the company's two regular Prius hybrids across the board. is a fantastic PR stunt, but is it good science?

What the project doesn't do is compare the environmental cost per person-mile to that of Google's private commuter bus fleet. Nor does it compare the total carbon footprint over time of a newly-manufactured plug-in electric hybrid to, say, converting an existing automobile or improving public transportation. But then, shiny new cars are the classic California status symbol, and alternative-fuel vehicles are just the latest form of conspicuous consumption — the paint job just screams, "Look at me and how environmentally conscious I am!" (Photo