Table B-2b. Estimated Measures of Reliability for Hazardous Material Shipment Characteristics by Hazard Class for the United States: 2012 and 2007
(Estimates are based on data from the 2012 and 2007 Commodity Flow Surveys)
| Hazard class and description | Value | Tons | Ton-miles (1) | Average miles per shipment | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Coefficient of variation of number | Standard error of percent change | Coefficient of variation of number | Standard error of percent change | Coefficient of variation of number | Standard error of percent change | Coefficient of variation of number | Standard error of percent change | |||||
| 2012 | 2007 | 2012 | 2007 | 2012 | 2007 | 2012 | 2007 | |||||
| Total | 3.1 | 2.6 | 6.5 | 3.7 | 3.3 | 5.8 | 6.2 | 4.6 | 7.4 | 7.8 | 8.1 | 13.4 |
| Class 1, Explosives | 17.6 | 17.6 | 39.0 | 21.7 | 14.1 | 34.4 | 13.5 | 13.0 | 20.9 | 3.7 | 8.7 | 10.8 |
| Class 2, Gases | 5.6 | 9.2 | 10.3 | 4.9 | 8.5 | 6.4 | 9.9 | 12.8 | 9.7 | 10.0 | 10.7 | 16.6 |
| Class 3, Flammable and combustible liquid | 3.6 | 3.3 | 8.4 | 4.1 | 3.3 | 6.6 | 8.1 | 2.7 | 9.6 | 9.3 | 18.6 | 21.4 |
| Class 4, Flammable solid; spontaneously combustible material; dangerous when wet material | 14.2 | 22.2 | 35.1 | 13.7 | 20.9 | 13.8 | 28.5 | 21.1 | 37.1 | 24.7 | 18.1 | 56.0 |
| Class 5, Oxidizers and organic peroxides | 9.3 | 10.6 | 15.9 | 10.3 | 15.0 | 14.7 | 17.5 | 18.9 | 20.0 | 11.5 | 9.8 | 18.4 |
| Class 6, Toxic materials and infectious substances | 14.6 | 22.0 | 18.9 | 28.4 | 13.9 | 21.3 | 23.3 | 15.7 | 17.9 | 10.2 | 14.7 | 19.6 |
| Class 7, Radioactive material | 34.5 | 25.7 | 25.6 | S | 35.8 | S | 35.7 | 24.0 | 45.6 | 36.3 | S | S |
| Class 8, Corrosive material | 6.3 | 5.9 | 12.7 | 8.0 | 9.4 | 13.6 | 9.1 | 16.1 | 15.7 | 14.0 | 14.3 | 25.4 |
| Class 9, Miscellaneous hazardous material | 9.4 | 10.5 | 27.0 | 17.2 | 9.7 | 15.9 | 12.7 | 12.5 | 12.4 | 19.4 | 16.3 | 27.7 |
KEY: S = Withheld because estimate did not meet publication standards.
(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.