[basjoos]

When you look at most roof top cargo boxes (Yakima, Thule, etc.), most of them are as un-aerodynamic as the vehicles carrying them and would present lower drag if they were mounted backwards. They tend to be wedge shaped with a rounded tapering front end, a broad flat back end, and don't appear to take into consideration the rising air flow coming off the windshield. In college, I used to car top a kayak and use it as a cargo box. It was more aerodynamic than any of the cargo boxes that I've seen on the road. How would you design a cargo box to meld in with the roof line of a car to produce a minimum of additional drag?