For years vortex generators where only frequently seen on owner-operator trucks. Higher fuel prices have pushed several major fleets into trying these devices.
Introduction & Rationale
Keeping the air flowing smoothly across the tractor-to-trailer started with cab extenders, sleeper extenders and most recently added sleeper top extenders to the cab. Some drivers and fleets have used vortex generators on the back edge of the cab or extenders to further guide the air flow to the trailer.
There are several suppliers of these systems. Some are installed individually while others come in longer strips to allow several to be installed simultaneously.
The improvement in fuel economy is small enough as to be below the noise level in test data. None of these systems is EPA Smartway certified as of January 2018 and they are not available as a factory installed option from tractor or trailer manufacturers yet.
Many drivers report that using these devices have keep their trailers cleaner due to the revised air flow.
Some of the products have a side benefit to make them more visible at night. Some glow in the dark while others have reflective surfaces to reflect headlights.
Handling and steering become easier if there is no wind buffeting of the trailer.