Aerodynamic Upgrades to Large Trucks Would Cut Fuel Use Steeply

The fuel consumption of the 2 million tractor-trailer trucks hauling cargo across the U.S. — which currently
Airflow patterns around a tractor-trailer truck
burn 36 billion gallons of diesel fuel per year — could be cut by billions of gallons through the use of drag-reducing devices, according to researchers at Lawrence Livermore National Laboratory. In wind tunnel tests, researchers fitted a scale-model truck with two types of devices designed to reduce drag and improve aerodynamics: a trailer skirt, which consists of panels affixed along the lower side edges of a trailer, and a boat tail fairing, which is affixed to the back of the trailer to reduce the size of its wake. The researchers found that using the devices in combination — technology currently installed on only 3 to 4 percent of the nation’s large trucks — reduced the aerodynamic drag by as much as 25 percent, which translates to a 13-percent decrease in fuel consumption. If the U.S. tractor-trailer fleet were to improve its fuel economy by 19 percent, which the researchers say is achievable, 6.5 billion gallons of diesel fuel would be saved each year, avoiding 66 million tons of carbon dioxide emissions.