Aerodynamic sleeper model shapes generally have rounded leading edges especially at the crown and grille edges, cab A-pillars, and sleeper roof edges. They generally have conformal headlamps integrated into the fenders, curved outer end to bumpers, bumper air dams, hoods that slope downward at the front, and aerodynamic cab access steps. They are designed to lower the drag of the front of the vehicle.
Since the early 2000s, aerodynamic sleepers have become the predominant type of tractors in production. Classic sleepers still exist with long and tall hoods, but sacrifice as much as 30% in fuel savings.
Due to lower drag
“We continue to update our fleet with more fuel efficient post-2014 U.S. Environmental Protection Agency emission compliant engines, install aerodynamic devices on our tractors, and equip our trailers with trailer blades, which all lead to meaningful improvement in fuel efficiency.” — Knight Transportation
“Appearance and detail of our equipment means a lot to our drivers. Drive wheel fairings don’t just save us money, but our drivers like them too.” — Brad Pinchuk, Hirschbach
“Sleeper tractor aerodynamics have been finely tuned by all OEMs. Eliminating various features can add 10% to a fleet’s fuel expense,” — Chief engineer at a major truck builder.
The Confidence Matrix has been issued to help fleets make decisions about tractor aerodynamic devices.