I have two NY issued E-ZPasses for my motorhome. One is configured with a vehicle class for four axles for when we have our toad with us, and the other for two axles. Both are included in the NY Thruway's "Motorhome Plan" where we get charged standard passenger per axle rates instead of the higher large vehicle rates trucks and buses pay. The transponder classes tell other E-ZPass states how many axles we have, but we don't get any extra discounts of course. I assume the other states also have their own axle count detection systems as well.