Monroe County, N.Y., fleet executive Maggie Brooks believes that "liquid propane is the real ticket" among alternative fuels. "A CNG fueling station costs more than $1 million. For pennies on those dollars, you can get a complete propane fueling station. It's a simple steel tank with a little pump on it," she said. The county's fleet consists of 700 vehicles that run on propane autogas, ethanol-gasoline blends, compressed natural gas and biodiesel.