Table B-2c. Estimated Measures of Reliability for Shipment Characteristics by Total Modal Activity for the United States: 2002 and 1993
Monday, July 2, 2012
Table B-2c. Estimated Measures of Reliability for Shipment Characteristics by Total Modal Activity for the United States: 2002 and 1993
[Estimates are shown as percents and are based on data from the 2002 and 1993 Commodity Flow Surveys]
| Mode of transportation | Ton-miles CV |
Std. error of percent | Average miles per shipment CV |
Std. error of percent | ||
|---|---|---|---|---|---|---|
| 2002 | 1993 | 2002 | 1993 | |||
| Total | 3.7 | 3.4 | 6.5 | 2.8 | 3.9 | 6.1 |
| Truck | 2.8 | 1.4 | 4.5 | 3.6 | 1.3 | 4.6 |
| Rail | 7.6 | 5.4 | 12.6 | 6.1 | 5.2 | 7.7 |
| Shallow draft | 9.4 | 11.1 | 14.8 | 13.1 | 5.1 | 16.3 |
| Great Lakes | 18.1 | 24.6 | 43.5 | 16.0 | 14.4 | 15.0 |
| Deep draft | 17.3 | 14.0 | 19.2 | 11.1 | 5.4 | 11.0 |
| Air | 15.7 | 6.2 | 25.2 | 4.3 | 3.9 | 8.0 |
| Parcel, U.S.P.S. or courier | 4.2 | 3.6 | 8.0 | 2.3 | 3.3 | 4.9 |
| Pipeline | S | S | S | S | S | S |
| Other and unknown modes | 9.7 | 11.6 | 7.2 | 13.0 | 14.4 | 11.0 |
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.