Table B-2c. Estimated Standard Errors for Shipment Characteristics by Total Modal Activity for the United States: Percentage of Total for 2012 and 2007
(Estimates are based on data from the 2012 and 2007 Commodity Flow Surveys)
| Mode of transportation (1) |
Ton-miles (2) — standard error |
|
|---|---|---|
| 2012 | 2007 | |
| Total | 0.0 | 0.0 |
| Truck (3) | 1.2 | 1.3 |
| Rail | 2.1 | 2.0 |
| Inland water | 0.9 | 0.8 |
| Great Lakes | 0.3 | 0.3 |
| Deep sea | 0.5 | 0.4 |
| Air | Z | 0.0 |
| Pipeline (4) | S | S |
| Parcel, U.S. Postal Service, or courier | Z | 0.0 |
| Other modes | Z | 0.1 |
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.