Does the cost of installing a airfoil on the cab roof of my truck offset any increase in gas mileage because of the aerodynamics? Does the airfoil effect handling of the truck while hauling a 35 foot ...
The more you can do to have a large frontal area vehicle combination only make "one hole" through the air the better = why it's harder to pull in a cross wind than head wind - the wind gets at all the gaps and clutter. The pointier the front and the more shaped like a fish the stern the better. The closer roof top fairings are to a trailer the better.