Table B-1a. Estimated Measures of Reliability for Hazardous Material Shipment Characteristics by Mode of Transportation for the United States: 2012
(Estimates are based on data from the 2012 Commodity Flow Survey)
|Mode of transportation||Value||Tons||Ton-miles (1)||Average miles per shipment— coefficient of variation of number|
|Coefficient of variation of number||Standard error of percent of total||Coefficient of variation of number||Standard error of percent of total||Coefficient of variation of number||Standard error of percent of total|
|Air (includes truck and air)||12.8||Z||29.3||Z||38.4||Z||8.7|
|Parcel, U.S. Postal Service, or courier||11.0||0.1||9.0||Z||10.4||Z||6.2|
|Truck and rail||14.5||0.1||15.6||0.1||14.0||0.8||9.2|
|Truck and water||S||S||S||S||S||S||14.1|
|Rail and water||30.6||Z||42.5||0.1||33.3||0.2||S|
|Other multiple modes||0.0||0.0||0.0||0.0||0.0||0.0||0.0|
KEY: S = Withheld because estimate did not meet publication standards.
Z = Rounds to zero.
(1) Ton-miles estimates are based on estimated distances traveled along a modeled transportation network. See “Mileage Calculations” section for additional information.
(2) “Truck” as a single mode includes shipments that were made by only private truck or only for-hire truck.
(3) 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/econ/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.