permitting and toll roads

This may sound silly, but being one of those "dang furriners" while in the US, I really do not know the answer.

For many years, I had my equipment registered iin WY, and used IFTA and IRP to move it all over the US. I no longer do that, and sold my share of the hardware to another company. While I am technically "retired", they have asked me to come back and move equipment with my tractor to worksites. I am only going to do this for a year or so (so I tell my long-suffering wife) so don't want the hassle of setting up IRP and IFTA for my little one-man company. That means permitting (we only know days in advance of where we are going, sometimes not even hours).

Well, the ###### permits cost more than the fuel to cross many states and provinces. I can not but help to have noticed over the years that there are seldom if ever any scales on toll roads. If I am crossing a state on a toll road, do I actually need a permit????

Trying to understand the concept as well as the law.

 

Yeah, I agree with the greed part, but what is the story of weigh scales on toll roads? I have never seen one. why is that? (we don't have ANY toll roads around here, so no idea what they are really all about)