Truck manufacturers use computers to stimulate how air circulates across surfaces of a model before prototypes are built.

If you want to know whether aerodynamic devices help fuel economy, ask Greg Decker, an owner-operator based in Calgary, Alberta. He’s installed aerodynamic equipment on his 2008 Volvo 780 tractor and 2002 Utility 3000R refrigerated trailer.

Decker, who has meticulously tracked his fuel performance after every tankful for seven years, says his commitment has made a difference. From Aug. 4 to Sept. 30, 2008, he got 6.05 miles per gallon. During the same period this year, his mpg was 6.81. He credits the Windyne Flex Fairings he had installed on his trailer this past summer.

Decker, leased to Caneda Transport, says he previously added aerodynamic mud flaps and airflow tabs to improve handling and curtail road spray, as well as get better fuel economy. “If there were other ways to improve, I would try,” he says.

A combination of higher fuel prices and equipment-altering regulations has the potential of changing how and where truckers will operate. Regulations planned by the California Air Resources Board will eventually require aerodynamic technologies, as well as low-rolling resistance tires, for all trailers that run in the state. All of this stands to change the intensity of owner-operators’ focus on their rigs’ aerodynamics.

Truck aerodynamics got little notice until the oil embargo in the early 1970s led to shortages and sharply higher fuel prices. In 1974 a federally funded study examined wind drag on a cabover with a 45-foot trailer and five add-on devices. Interest waned, however, as oil prices declined.

Beginning in the mid-1980s, truck manufacturers introduced more aerodynamically styled models. Most owner-operators, however, remained loyal to their boxy-hooded vehicles as fuel prices stayed low. More aerodynamic truck models emerged in the 1990s and the first of the trailer components designed to redirect airflow soon followed.