Most of today’s long-haul tractors are equipped with aerodynamic devices that can bring up to 30% fuel improvements over previous generations however, day-cabs can also realize the benefits of drag reduction, according to the latest Confidence Report from the North American council for Freight Efficiency.

The NACFE looked into tractor aerodynamic efficiency and found that the newest sleeper models from OEMs were good enough most fleets looking to improve aerodynamic efficiency. OEM models have already been optimized to provide the best performance for most fleet needs, according to the report.

The one area where this was not the case was in day-cab models where the common convention is that speeds are too low for significant savings from aerodynamic efficiency. According to the report, if fleets pursued greater adoption of aerodynamics they could see fuel efficiency gains in all operating environments. In portions of driving at highway speeds, aerodynamic improvements could increase fuel efficiency by as much as 13%.

Aerodynamic technology has traditionally lagged behind in day-cab truck development. The NACFE is recommending that tractor manufacturers should design and offer more aerodynamic features for day-cab tractors including those running on natural gas. This is partly due to an industry shift toward shorter hauls which will cause more day-cab fleets to see significant highway and interstate miles, according to the report.

Another reason for increased focus on day cabs is future emissions regulations from the EPA and NHTSA which will require day-cab models to catch up to their sleeper cousins.

“Tractor aerodynamics pay for themselves,” said Mike Roeth, operation lead at Trucking Efficiency. “Don’t buy a tractor without them, if you do you’ll regret it.”

The Full Confidence Report and executive summary can be found here.