^^^ dunno where you live, but around CA or wherever else i drive i have to say 18 wheelers 99.9% of the time are doing a good job of staying in proper lane
if its around LA and its 3-5 lane freeways , they always stick to right 2
on 2 lane freeways, unless passing *(which yes can take a while for them) i've never seen one just cruising in the Left