How much driving does a trucker average in a day?
Unless there’s a wreck it seems to be a no maintenance item. How many miles does a driver do in a year? This is on the trailer, so I’d expect it to be mounted on trailers owned by the folks that own the tractor.
My estimate: if you assume the truck does 400 miles per day, 250 days per year, that’s 100,000 miles per year.
That seems to jive with the comments posted here by purported truckers, where they are talking about numbers ranging from 2300-3200 miles per week (120K-166K miles per year).
So according to Terr’s math, the device could pay for itself in less than a year. Since it’s just a passive thing, it probably lasts a long time; once the trailer is at the end of its service life, you could probably move the device to a new trailer and keep on truckin’.
The longevity seems to be good. The maker’s site has a pic of a trailer that was backed off some sort of vehicular cliff, almost as if the trailer was in a warehouse and went backwards off the dock, and most of the trailer’ weight was crushing the deflector. Once they picked up the trailer, the deflector popped back into shape.
Seems like a no-brainer. Cheap to buy, no maintenance, pays for itself in a few months. The only major obstacle I can see is when trailers are owned by someone and the tractors are owned by someone else. The cost is borne by the trailer owner but the tractor owner/operator realizes the benefit.
Perhaps the tractor owning company would offer a small discount if your trailer has one of these devices? I’ll have to watch and see if there’s a match between the tractor and trailer markings.
I see you also have a photo of the last remaining box of .22LR on the planet! 
Want some?
I don’t like it. Doesn’t load correctly in my Henry rifles. The sharp edge on the projectile keeps it from entering the chamber correctly.
Wow, less than a year to pay it off? And that much less fossil fuel burned? Very cool innovation right there.
How come the back is open? Seems like you’d get a lot more turbulence that way, reducing the aerodynamics.
Probably cost and weight. Leaving the back open is simply cheaper, and lighter.
They may have tested a closed back and discovered that fuel savings were’t that much better.
Given its layout and locale, I wouldn’t expect much turbulence from it.
Serious question: Are you left-handed? I glanced at the picture and assumed the wider end was facing forwards. I’m left-handed and it seems we imagine things facing to the right; that’s how I naturally draw animals, as well as vehicles, in profile. I wonder if being left-handed also influenced our assumptions about that photo.
Or maybe I just subconsciously noticed it was in the outside lane and, living in a place where we drive on the left, assumed the truck was moving left to right.
There ain’t no vermouth in that martini. 
Right-handed. But serious about the physics of braking. When you either reach the point of full-stop or release the brake, the created g-forces relax and release your body. Backwards you go.
The only reason for that to happen would be gravity, if you were to end up at the top of the chute due to inertia during the braking, and the greater slope at the top caused you to roll back down. Is that what you mean? I would think that would be fairly easy to avoid if you stay near the top, with a good enough hold on something that you can avoid rolling down. You should only have to fight gravity and modest acceleration, and you should have some friction on your side.
All that said, I didn’t study physics past 18, so I don’t have too much confidence that any of it is right.
Well, the inside of these have appeared perfectly smooth to me when I have seen into them on trucks. So there is nothing to grab to keep you from sliding out.