Re: What is the hairy skirt thing hanging off the rear bumper for?
My theory is that the skirts do a better job of allowing water to drip back down to the road, because of all the extra surface area, than a flat mudflap would have. While going down the road in a rainstorm the moisture thrown from the tire hits a mudflap and large amount blows around it, but when it hits the skirt, it gets more of it becomes absorbed by the skirt and runs down.