|U.S. total land trade2||U.S. total water trade||U.S. total air trade||Other and unknown3|
1 BTS estimated the export weight for truck, rail, pipeline, and other and unknown based on value-to-weight ratios from the import data. This estimation procedure was used because U.S. exporters are not required to report the export weight for land modes. Weight for water and air exports and imports are from U.S. Department of Commerce, U.S. Census Bureau.
2 Includes truck, rail, pipeline, and miscellaneous surface modes.
3 Includes purchased vehicles such as aircraft or boats moving from manufacturer to customer where the vehicle itself is the shipment, pedestrians carrying freight, and miscellaneous.
SOURCE: U.S. Department of Transportation, Bureau of Transportation Statistics, based on: Value data -- total trade, from U.S. International Trade Commission, USITC Interactive Tariff and Trade Dataweb, available at http://dataweb.usitc.gov/, as of September 15, 2004; weight data -- Foreign Trade Division, U.S. Exports of Merchandise, CD-ROM and U.S. Imports of Merchandise, CD-ROM, December 2003. Truck, rail, pipeline, other and unknown data-USDOT, BTS, Transborder Surface Freight Data 2004; and special calculation, October 2004.