My ipass is linked to all my vehicles. At least in my state, Illinois, I do not even need the ipass with me as they scan the license plate as you go through. I am told it works in other states, however since I have it with me anyway, have never "tested" that theory. I know the ipass works at least any place that ezpass works, which currently is Illinois, Delaware, Indiana, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, Virginia and West Virginia. Having said that, the tolls vary greatly, which for those of us that live in Illinois are used too since it can vary here from toll to toll on same road. Almost every one of these states, maybe all, offer significant discounts for using the ipass/ezpass. There is no cost for the ipass transponder although it needs to be linked to a credit card or bank account to keep it "filled". Transponders are same for all vehicles. ipas is about the size of a cigarette pack (a little thinner.