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 | ||
| Total | 3.7 | 0.0 | 3.2 |
| Truck (3) | 1.6 | 1.2 | 4.1 |
| Rail | 8.1 | 2.1 | 3.6 |
| Inland water | 14.6 | 0.9 | 15.2 |
| Great Lakes | 26.1 | 0.3 | 13.7 |
| Deep sea | 23.7 | 0.5 | 7.5 |
| Air | 15.0 | Z | 13.4 |
| Pipeline (4) | S | S | S |
| Parcel, U.S. Postal Service, or courier | 2.5 | Z | 2.7 |
| Other modes | 22.7 | Z | S |
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.