Tractor-trailer trucks may leave a different "footprint" in the near future. Heavy trucks outfitted with single wide-based tires instead of the conventional dual tires are more fuel efficient, according to a study sponsored by DOE's Office of Vehicle Technologies. A paper from DOE's Oak Ridge National Laboratory reports that Class 8 heavy trucks equipped with new-generation wide-based single tires instead of the familiar dual tires get markedly better mileage, which improves as more single-tires are installed on the truck. Fuel economy improved around 6 percent when either the tractor or the trailer was equipped with the single-wides and more than 9 percent when both were mounted with single-wide tires. The paper, by Oscar Franzese and Helmut Knee of ORNL and Lee Slezak of DOE, has been named to receive the Transportation Research Board of the National Academies Pyke Johnson Award for the Best Paper in the Area of Planning and Environment.