Study: Improvements in Large Truck Aerodynamics Could Save US Nearly One Billion Gallons of Fuel Annually
The widespread application of new aerodynamic technologies on tractor-trailer trucks could cut US fuel consumption by nearly one billion gallons per year, according to the results of a two-year collaborative study conducted by members of the Truck Manufacturers Association (TMA) and the US Department of Energy (DOE).
Four TMA members—International Truck and Engine Corporation, Freightliner LLC, Mack Trucks, Inc. and Volvo Trucks North America—representing 75% of the US market for Class 8 trucks teamed with the DOE to study a variety of design improvements that would reduce aerodynamic drag and significantly improve fuel efficiency.
Technologies that improve truck aerodynamics in several key areas include:
- Gap Enclosure: reduces aerodynamic drag in the gap between the tractor and trailer.
- Side Skirts: improves aerodynamics and reduces airflow under the trailer in crosswinds.
- Boat Tails: tapers back of trailer to minimalize wake airflow.
- Side Mirror Design: reconfigures shape and support systems to reduce aerodynamic drag.
The combined effect of all aerodynamic improvements on one vehicle could result in as great as 23% reduction in aerodynamic drag. For every 2% reduction in aerodynamic drag, there is a 1% improvement in fuel efficiency.
To put this in perspective, if every tractor/van semi-trailer combination truck in operation in the US adopted these technologies and improved fuel efficiency by 10%, it would translate into nearly one billion gallons per year of fuel savings. These small improvements collectively could make a huge difference in reducing fuel use.—Robert Clarke, president of the Truck Manufacturers Association
The calculation of one billion gallons is based on the Census Bureau’s 2002 Vehicle Inventory and Use Survey (VIUS). It assumes 750,000 tractor/van semi-trailer combination-unit trucks in operation traveling a total of 60,101 million miles. A 10% improvement in average fuel economy from 5.5 mpg to 6.05 mpg results in saving approximately 993.4 million gallons of fuel per year.
The two-year study was funded by the US Department of Energy FreedomCAR and Vehicle Technologies Office through the National Energy Technology Laboratory. The Truck Manufacturers Association is a not-for-profit technical trade association headquartered in Washington, DC. Members are corporations with principal headquarters located in North America who engage in the design, development, manufacturing, marketing and sale of Class 6, 7, and 8 medium and heavy-duty trucks.