A per-mile tax charged by a handful of states on heavy vehicles.
Kentucky, New Mexico, New York and Oregon each run their own version, charged on miles driven in-state at weight, and each requires its own registration or permit.
It is separate from IFTA and easy to miss because it only applies in four places. Running through one of them without the permit is a citation, not an oversight.
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Inteleri works out what a load actually pays you once things like this land. See how it works.