How many hours can you work per day with a class B CDL?

Well, according to the FMCSA, you're still bound by the 11/14/70 hour Hours of Service regulations. However, if your company gets audited, and there's no logbooks to show, they look at how many hours their employees worked weekly. But even that's a bit difficult for the DOT to go on, since, if a company claims you didn't drive a CMV once you reached the 70 hour mark, how is the DOT going to prove otherwise? I've worked the oilfields and I've hauled for a road construction outfit (albeit with a Class A, but the regs are the same), and have worked shifts of up to 30 hours. There's that which they can do, and that which they can get away with.