She accelerates gently when the light turns green, and coasts down hills to save gas. On highways, she stays in the right lane and watches the big SUVs zoom past.

"When I see someone roar past me, I think, `They just used enough gas to last me a week,'" she said.

She is part of a small and extremely dedicated group of drivers around the country who call themselves "hypermilers." They almost exclusively drive hybrid vehicles, and their goal is simple: squeeze every mile they can out of each drop of gas.

But Gerdes isn't just slow. He's deliberate. And he's the best hypermiler in the world. Hypermiling? What's that, you ask? It's the art of getting the most mileage out of every drop of gas in your tank. Gerdes never uses air-conditioning. He takes alternative routes to avoid red lights. Stepping on the brakes just wastes gas in his estimation. And he's known to tailgate 18-wheelers and let them pull him along.

Before this car I spent two years learning hypermiling on my 2004 HCH1.