Fleet managers are well aware that aerodynamic drag (wind resistance) accounts for most truck energy losses at highway speeds. Reducing drag improves fuel efficiency. The longer the drive and the higher the speed, the greater the potential efficiency benefits become.
Over the past two decades, manufacturers have made significant progress in reducing the drag coefficient (a measure of wind resistance) of a typical freight truck from about 0.8 to about 0.65—an improvement of nearly 20%. The Environmental Protection Agency (EPA) suggests that additional efforts to improve aerodynamics could result in a further 25%, reduction in the drag. This could have a significant impact on fuel economy. For example, cutting drag by 20% could boost fuel economy up to 15% at highway speed, according to the agency.
A number of options exist to improve aerodynamics and improve fuel efficiency. The truck/tractor aerodynamics include an number of modifications such as, roof fairings, side extender and side tank fairings, aerodynamic front bumper and mirrors. The trailer aerodynamic options include side skirts or fairings, wheel covers and boat-tails at the back of the trailer.
An aerodynamic long-haul combination truck can realize a fuel economy increase of 11%, as compared to a typical long-haul combination truck. This would result in about 1,600 gal. saved, reducing fuel costs by over $6,000 and saving 16 metric tons of carbon dioxide. Some fleets have reported that the initial expense of installing aerodynamic features can be quickly recouped through fuel saving. Those fleets that are taking the plunge and equipping trailers with aerodynamic devices are seeing better fuel economy.
Right now their choice is an option, but in the future aerodynamic improvements will likely be mandated as we continue to move toward improving fuel efficiency as outlined in the EPA and Department of Transportation’s Highway Traffic Safety Administrations Greenhouse Gas reduction initiatives.
For tractor/trailer fleets, the focus of those initiatives includes making their rigs as aerodynamic and fuel efficient as possible.