To correct the comprehensive post above.

Line holders are generally UP TO 17-18 days off but not the norm. There are many many 13 day off 72hr uncommutable lines.

Also, we do not have a min day. We have a min duty period of 4hrs for one duty period trips and 4.5 for multi duty period trips. I have seen 10hr 3day(two duty period) trips and 14hr 4 day(three duty period) trips. It's a total scam