The IRP serves as an organization similar to IFTA.  The state where the truck resides and it is registered to is assigned to administer the IRP process on behalf of the rest of the states for which the truck purchased IRP licenses from.  IRP filling with the different state jurisdiction is based on the annual IFTA reported traveled miles, truck components specifics among other details.  Registration and truck tag is provided by the residence state, but authorizes the truck to travel throughout each of the States jurisdiction for which registration was paid and obtained.