[aerohead]

Originally Posted by pasadena_commut

I've seen tests of up, down, mesh, covers, and partial covers. However I have not seen anybody try louvers. Naively it would seem like better flow might be achieved by placing a series of horizontal louvers (perhaps just thin boards) where the tailgate used to be. If it's too turbulent side to side vertical lovers could also be added. With proper design it might straighten the flow out of the bed of the truck. Might.

Louvers would be like "gate off".