IRP is for apportionable vehicles, defined as commercial motor vehicles engaged in interstate commerce (i.e., operating in more than one jurisdiction) with power units that meet one of the following criteria:

Have a gross vehicle weight (GVW) over 26,000 pounds; or
Have three or more axles, regardless of weight; or
Are used in combination with a trailer for a combined GVW that is over 26,000 pounds.
IRP is a reciprocal agreement, meaning that when the vehicle is registered in the jurisdiction where the motor carrier is based, the registration is valid in all the other IRP member jurisdictions. Additionally, the IRP registration is “apportioned” because the fees paid to the base jurisdiction are divided among all the member jurisdictions in which the vehicle(s) operated. IRP member jurisdictions are the the lower 48 states, the District of Columbia, and the 10 Canadian provinces.