I forgot Purolator was still in biz up there -- ours got absorbed by someone, UPS maybe. But you may be onto something with the employee reward thing.
I recall seeing these on the highways here (not many though).
They claim to give a 4% increase in economy using the "SAE J1321" testing method (taken from http://www.freightwing.com)
Any fuel savings on large, long-distance carriers could help big-time. I haven't seen much in the wheel-covering department.
Thanks man! :-) I don't think they cover the trailer's wheels because the wheel-set has to slide fore and aft to balance the load. On fixed-axle vehicles, there has to be a significant benefit in a wheel cover of some sort. Anyways, the picture probably shows the axle group in the front-most position.