I don't know if that's what they are called, but coming home on the 4 hr. drive from Vegas this morning, we saw dozens of semis (some doubles) with the white/lt.cream colored big sleeper cabs with brown UPS emblems on the cabs. I have not seen so many before. Why the difference now. I thought maybe they were relying less on trains, but I also saw the long trains in the San Bernardino mtns. with UPS trailers on them. Is something new now? There were just so many of them.