I've only seen two trailers with them on. Skirting that extends the side of the trailer down, nearly to road level. From behind the drive tires almost back to the trailer tandems. My best guess would be that this is one of the latest ideas to improve fuel economy, but I'd be willing to bet it will also have an effect on a wet road and when there is loose snow on the surface. It may reduce what the driver behind gets to try to look through... And, again, maybe not.

But, looking at them, I have to wonder just how long they will last. While over a period of time, they may be cost effective with fuel savings, but I'm wondering about the repairs. I can easily see a driver making a corner into a shipper or receiver, and trying to move the snowbank over in the process. If it starts pushing the ridge of snow over to the side, which one wins? The skirting? Or the snow bank?

I did not look closely enough to see just what they are made of, and if they are flexible enough to take that kind of beating. Just wondering if anyone else knows about them.