The North American Council for Freight Efficiency (NACFE) has revised its Tractor Aerodynamic Devices and Trailer Aerodynamic Devices confidence reports. Originally published in 2016, several equipment developments led NACFE to revise the reports.

In the case of tractor aerodynamics, the most significant development has been a focus on drivewheel fairings, tractor-trailer gap devices, and the replacement of mirrors with cameras. In general, tractor aerodynamic technologies and strategies are constantly and rapidly evolving as truck OEMs continue to optimize their base models to reduce aerodynamic drag.

The report recommends that fleets remove aerodynamic options from the manufacturer-recommended sleeper aero configurations when justifiable reasons are identified in a specific duty cycle. Once the fleet has selected a base model, there are additional options for optimizing the tractor’s aerodynamics, which can help fleets exceed 10 mpg.

The report also found that there is still work that needs to be done on aerodynamic devices for day cabs and alternative-fueled vehicles in order for fleets to see fuel savings.

The biggest development noted in the trailer aerodynamic report was the sunsetting of first-generation trailer tail devices and the rise of a new generation of rear devices that address some of the concerns with first-generation devices, including driver acceptance and docking.

The per-vehicle fuel economy benefit of trailer aerodynamic devices can be high, ranging from 1% to more than 10%, depending on the devices chosen with priority given to underbody devices followed by rear devices and then tractor-trailer gap devices. The revised study concluded that while trailer aero devices have matured, they will continue to improve and become lighter, more robust and less expensive thereby improving their payback.