Car Runs Mostly on Air

Developer Zero Pollution Motors is working on a compressed air vehicle (CAV) that could run "all day on nothing but air and a splash of salad oil, alcohol or possibly a pint of gasoline." Cost: $20,000. Timing: 2011.

As far back as 2005, however, experimental vehicles were getting up to 250 mpg. Getting these sorts of vehicles into production requires serious industry and political willpower, not just hot air. Meantime, there are a slew of hybrid SUVs and trucks that get around 21 mpg ... progress?

[How Hybrids Work]

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