A significant factor affecting fuel use is aerodynamic resistance, commonly known as drag. Studies by the Rocky Mountain Institute and others have shown that drag is a large factor in fuel use, and that a reduction in drag will reduce fuel consumption at both urban and highway speeds. For tractor-trailer combinations, about 70% of drag is due to the trailer.
Some of the devices heavy-duty commercial trucking can consider to reduce drag include:
Many OEM and aftermarket manufacturers are selling these devices today. For a look at the experience of BC fleets piloting some of these technologies, see Fleet Experiences.
For more on aerodynamics, see: Truck Efficiency and GHG Reduction Opportunities in the Canadian Truck Fleet (2007): a report of the Rocky Mountain Institute.
Also see a May 2003 article on highlights of a US Lawrence Livermore Labs analysis on the impact of drag on fuel efficiency in large tractor-trailer combinations: “Reducing Aerodynamic Drag”.
A recent Freight Wing study on trailer fairings showed that this aerodynamic feature could offer a 6.4% savings in fuel consumption and pay for itself in 1.1 to 2.2 years.