The new freight totals are larger than the value-added and final weight of materials used in products purchased by consumers and other end-users. Also, the total value of shipments is not directly comparable to the national Gross Domestic Product (GDP) because GDP measures the value added or net output of production. The value of goods measured in the CFS includes the market value of goods used in production as well as final demand; hence the goods may be counted more than once in the production life cycle.
While the composite estimates of total freight shipments provide the most complete commercial freight picture for all modes of transportation, they exclude most government shipments, except municipal solid waste.
The new national composite estimates define a shipment in a similar manner as defined in the CFS. A shipment is a single movement of goods, commodities, or products from an establishment to a single customer or to another establishment owned or operated by the same company as the originating establishment (e.g., a warehouse, distribution center, or retail or wholesale outlet). Shipments are recounted every time the goods change hands from one establishment to another. Full or partial truckloads are counted as a single shipment only if all commodities on the truck are destined for the same location. If a truck makes multiple deliveries on a route, each stop is counted as one shipment.
For the sectors covered in the CFS, a shipment is counted to represent a transportation movement and measures the true origins and destinations as contrasted with terminal-to-terminal movements. Even where shipments are carried by more than one transportation mode, the shipment information covers the ultimate origins and destinations. However, because the CFS data are from shippers and not carriers, the data do not accurately measure intermodal combinations used for transporting the goods. This lack of accurate modal information affects the level of intermodal shipments, because some of these shipments are grouped into other and unknown modes.
For the non-CFS sectors, shipments represent the total goods generated, handled, or transported by that sector. Because actual information on true origins and destination is not available for nearly all these non-CFS sectors, the new estimates cover an approximate distance representing the average distance traveled by particular commodities and transportation modes. This is particularly the case for merchandise imports, where detail information on ultimate domestic destination of goods by commodity and mode or whether and where the goods changed hands are nonexistent. And so, for example, the value and tonnage of imported freight are not counted multiple times as the goods arrive at U.S. ports and are transported to their true final destinations elsewhere in the country or to local warehouses and distribution centers. However, if the imports happen to be transported to a domestic U.S. establishment that is covered by the CFS, then those goods will be measured by the CFS and as such will be double counted in these new composite estimates. Currently, BTS and FHWA do not have the information necessary to remove such potential double counting.