Table B-2b. Estimated Measures of Reliability for Shipment Characteristics by Total Modal Activity for the United States: 2002 and 1997
Monday, July 2, 2012
Table B-2b. Estimated Measures of Reliability for Shipment Characteristics by Total Modal Activity for the United States: 2002 and 1997
[Estimates are shown as percents and are based on data from the 2002 and 1997 Commodity Flow Surveys]
| Mode of transportation | Ton-miles CV |
Std. error of percent change | Average miles per shipment CV |
Std. error of percent change | ||
|---|---|---|---|---|---|---|
| 2002 | 1997 | 2002 | 1997 | |||
| Total | 3.7 | 2.3 | 5.3 | 2.8 | 2.6 | 4.3 |
| Truck | 2.8 | 1.7 | 4.1 | 3.6 | 2.8 | 4.9 |
| Rail | 7.6 | 5.3 | 11.3 | 6.1 | 2.6 | 6.6 |
| Shallow draft | 9.4 | 5.5 | 12.9 | 13.1 | 20.9 | 44.5 |
| Great Lakes | 18.1 | 14.1 | 29.5 | 16.0 | 10.8 | 17.7 |
| Deep draft | 17.3 | 17.3 | 26.2 | 11.1 | 13.0 | 19.2 |
| Air | 15.7 | 7.8 | 17.1 | 4.3 | 1.8 | 6.6 |
| Parcel, U.S.P.S. or courier | 4.2 | 4.0 | 6.6 | 2.3 | 2.6 | 3.8 |
| Pipeline | S | S | S | S | S | S |
| Other and unknown modes | 9.7 | 8.5 | 7.8 | 13.0 | 9.6 | 17.2 |
KEY:
– Represents data cell equal to zero or less than 1 unit of measure.
S Estimate does not meet publication standards because of high sampling variability or poor response quality. CV Coefficient of variation of number.
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: Bureau of Transportation Statistics (USDOT) and U.S. Census Bureau, 2002 Commodity Flow Survey, United States Data, December 2004.