Heavy trucks use retreads because they have redundancy. 18 wheels, one blows no problem. 4 wheels, one blows big problem. I know and do work for many long haul truckers who have said that if they never had backup (18 wheels), they would never use them, and they never put retreads on the front. These guys make my mileage numbers look like small fry. I have over 1,000,000 miles under my *** because of work, but they do that in 1/4 of the time that I did. But they know (as do I) about how much weaker retreads are and are not "made" to the same exacting standards as new tires for roundness and balanceing.