Being from Delaware I have Delaware EZ Pass transponders for all my vehicles. If I'm pulling any kind of a trailer with my pickup, the system counts axles, and charges me as appropriate. This happens in all different states, and I believe I have used it in almost all places that accepts EZPass. I have a separate EZPass for my RV, and it behaves the same. If I'm pulling a toad, I have to put the toad transponder in a special envelope so I don't get charged twice for it. I have used the RV system (while pulling the toad) all the way from Maine to Illinois and down into Florida without a problem.