Table B-17. Estimated Measures of Reliability for Hazardous Material Shipment Characteristics for Selected NAICS (1) Codes for the United States: 2012
(Estimates are based on data from the 2012 Commodity Flow Survey)
| NAICS code | NAICS title | Value | Tons | Ton-miles (2) |
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 | |||
| Total | 3.1 | 0.0 | 3.7 | 0.0 | 6.2 | 0.0 | 7.8 | |
| 324 | Petroleum and coal products manufacturing | 4.6 | 1.4 | 4.7 | 1.5 | 14.4 | 3.4 | 6.7 |
| 325 | Chemical manufacturing | 5.8 | 0.5 | 6.0 | 0.5 | 7.8 | 1.9 | 4.8 |
| 424 | Merchant wholesalers, nondurable goods | 4.6 | 1.4 | 5.5 | 1.5 | 10.5 | 1.7 | 12.6 |
| 4246 | Chemical and allied products merchant wholesalers | 10.6 | 0.2 | 12.7 | 0.3 | 10.9 | 0.3 | 11.1 |
| 4247 | Petroleum and petroleum products merchant wholesalers | 5.1 | 1.6 | 5.9 | 1.6 | 10.5 | 1.2 | 15.0 |
| 4931 | Warehousing and storage | 31.1 | 0.7 | 34.3 | 0.6 | 21.3 | 0.3 | 21.5 |
(1) NAICS codes shown are those covered in the Commodity Flow Survey.
(2) Ton-miles estimates are based on estimated distances traveled along a modeled transportation network. See “Mileage Calculations” section for additional information.
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>.
NAICS codes shown had the highest estimated weight without considering sampling variability and are shown in descending order.
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.