scale

Cat is just the name of the company that installs the drive on/off scales at most truck stops. It is like calling all copies xerox. There are three separate plates to the scale. One for the steer wheels, one for the drive wheels and one for the trailer wheels. You park with the appropriate wheels on the appropriate plate, hit the talk button and when they answer tell them you are an RV. They will say ok and then you pull off the scale and go inside and get the weight ticket with the three weights and a total listed. IF you are concerned about your hitch weight then you can disconnect in the parking lot and go back to get just the truck weight without the trailer attached. This time you say it is a reweigh and you pay a reduced cost and get the new ticket. Compare the two drive wheel weights to get your hitch weight. I am generally more concerned about individual axle weights so I split my front and rear trailer axles on the reweigh between the drive and trailer plate. Try to avoid spending to much time on the scale since there are commercial drivers that want to get on too.

Here's a link for Cat Scale locator