Table B-2a. Estimated Measures of Reliability for Shipment Characteristics by Total Modal Activity for the United States: 2012
(Estimates are based on data from the 2012 Commodity Flow Survey)
|Mode of transportation (1)||Ton-miles (2)||
Average miles per shipment
coefficient of variation of number
|Coefficient of variation of number||Standard error of percent of total|
|Parcel, U.S. Postal Service, or courier||2.5||Z||2.7|
KEY: S = Withheld because estimate did not meet publication standards.
Z = Rounds to zero.
(1) Estimates represent activity for a given mode across single and multiple mode shipments. For example, “Truck” ton-miles includes total ton-miles for shipments moving only by truck plus ton-miles for truck segments of multiple mode shipments.
(2) Ton-miles estimates are based on estimated distances traveled along a modeled transportation network. See “Mileage Calculations” section for additional information.
(3) “Truck” as a single mode includes shipments that were made by only private truck or only for-hire truck.
(4) Estimates for pipeline exclude shipments of crude petroleum (SCTG 16).
NOTES: The Introduction and appendixes give information on confidentiality protection, sampling error, nonsampling error, sample design and definitions. Links to this information on the Internet may be found at <www.census.gov/cfs>.
SOURCE: U.S. Department of Transportation, Bureau of Transportation Statistics and U.S. Department of Commerce, U.S. Census Bureau, 2012 Economic Census: Transportation Commodity Flow Survey, December 2014.