[Motor31]

I can't comment on Canadian regs, sorry.

As far as US regs are concerned, if your truck is registered as a commercial truck you must stop at the scales.

To date I have not seen any scale signs indicating RV's must stop. That does not mean a commercial truck pulling an RV is exempt, the tow vehicle must not be registered as commercial. If the tow vehicle is registered as a non commercial truck and the sign says all trucks must stop then you must stop. It's the same when your tow vehicle, again registered as a truck, has a GVW of over 26,000 lbs. or the sign lists a range of GVW's that includes your truck's weight.

The only time I have had any DOT person do anything but wave us through a scale was in AZ. and the supervisor corrected the inspector before I got the paperwork out. It's pretty obvious that the RV folks will not be in excess of 80,000 lbs GCVW so the scale is pretty superfluous.