When it comes to putting a cap on gas guzzling, how you drive is almost as important as what you drive. “Fuel economy suffers at speeds higher than 60 and drops like a stone above 70,” says Chris Grundler of the National Vehicle and Fuel Emissions Laboratory, in Ann Arbor, Michigan. Adds Richard Beard, an associate professor at Utah State University who researches fuel efficiency, “Slowing from 70 to 55 can increase your miles per gallon by 15 percent.” Putting the brakes on “jackrabbit starts” (stomping on the gas after a red light) cuts use by 25 percent, says Grundler, and cruise control also saves fuel. Limit use of gas-chugging air conditioners and defrosters, and unload extra junk, since “you lose one mile per gallon or more for each 300 pounds,” notes Beard. Avoid idling, he advises: “One minute of idle is almost equal to starting the car.” Finally, leave the car lot with the best gas hoarder by consulting before you buy.