how do these guys do it??????????

As I understand it from the DOT you at least need to be running under an MC number, your own or someone else's where your truck is registered, if you're hauling commercial. And you have to have insurance. And you need to comply with requirements for fire extinguishers, road flares/signs, etc. It doesn't matter what weight you're working with.

If you get pulled over you'd better be able to prove that your load is not a for-hire or you're gonna get a probe that makes an alien abduction look like a grade school pop quiz.

The DOT people on the highway are pretty good at judging the weight of a load. If you're running heavy, you're gonna get caught eventually. I run with MC and DOT numbers and I get scaled pretty frequently. I'm careful to haul under my limits, and I place loads carefully on the trailer so the truck doesn't squat. I usually get waved on through the scale houses, and only have to stop on the scales occasionally.

 

How do you know he didn't have prepass??

 

In some states the left lane will red light you. In others it doesn't matter what lane you are in. I always hit the middle lane before the Knoxville, TN scales because the pressure plates in the right lane are bone jarring rough. Always get a green light. In VA, though it has been years since I rode up 81, the left lane was an automatic red light every time.