Table B-2a. Estimated Measures of Reliability for Hazardous Material Shipment Characteristics by Hazard Class for the United States: 2012
(Estimates are based on data from the 2012 Commodity Flow Survey)
| Hazard class and description | Value | Tons | Ton-miles (1) | 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 |
| Class 1, Explosives | 17.6 | 0.2 | 21.7 | Z | 13.5 | 0.1 | 3.7 |
| Class 2, Gases | 5.6 | 0.3 | 4.9 | 0.4 | 9.9 | 0.9 | 10.0 |
| Class 3, Flammable and combustible liquid | 3.6 | 0.6 | 4.1 | 0.4 | 8.1 | 1.5 | 9.3 |
| Class 4, Flammable solid; spontaneously combustible material; dangerous when wet material | 14.2 | Z | 13.7 | 0.1 | 28.5 | 0.5 | 24.7 |
| Class 5, Oxidizers and organic peroxides | 9.3 | Z | 10.3 | 0.1 | 17.5 | 0.4 | 11.5 |
| Class 6, Toxic materials and infectious substances | 14.6 | 0.1 | 28.4 | 0.1 | 23.3 | 0.2 | 10.2 |
| Class 7, Radioactive material | 34.5 | 0.2 | S | S | 35.7 | Z | 36.3 |
| Class 8, Corrosive material | 6.3 | 0.2 | 8.0 | 0.4 | 9.1 | 1.0 | 14.0 |
| Class 9, Miscellaneous hazardous material | 9.4 | 0.2 | 17.2 | 0.3 | 12.7 | 0.9 | 19.4 |
KEY: S = Withheld because estimate did not meet publication standards.
Z = Rounds to zero.
(1) 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>.
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.