The Commodity Flow Survey (CFS) is conducted as part of the Census Bureau's Economic Census, occurring every 5 years. It is the primary source of national and State-level data on domestic freight shipments in the United States. The survey sampled approximately 100,000 business establishments quarterly in 2007. The CFS measures domestic freight flows from establishments in mining, manufacturing, wholesale, and selected retail industries, as well as shipments from auxiliary establishments.1 The 2007 CFS was undertaken through a partnership between the Research and Innovative Technology Administration's (RITA) Bureau of Transportation Statistics (BTS) in the U.S. Department of Transportation, and the Census Bureau in the U.S. Department of Commerce.
This report summarizes and highlights freight shipments for each of the 50 States and the District of Columbia based on the final release of CFS data in December 2009. It provides tables for each State's value and weight of shipments, major commodity shipped, mode of transportation used, distance shipped, State of origin, State of destination, and industry. CFS data in its entirety for 2007 is available through the Census Bureau's American FactFinder at www.census.gov.
Tables in this section present data for all 50 States and the District of Columbia and show the value, weight, and ton-miles of commodity shipments by mode of transportation as estimated in the 2007 CFS.
In the South geographic region2, eight States and the District of Columbia had more than 80 percent of the value of originating shipments transported by truck. Only Louisiana and Texas had truck mode shares below 60 percent.
For the Northeast3 region, New Hampshire was the only State with a truck mode share under 70 percent. The States in the West4 region generally had the lowest shares of values carried by truck. Six States in the West region had under 60 percent of originated freight by value transported by truck, and only Arizona and Nevada had mode shares for truck exceeding 70 percent (figure 1).
In the Northeast region, all States have mode shares for truck exceeding 75 percent. In contrast, the West region only had 4 of 13 States with mode shares for truck over 75 percent.
North Dakota, New Mexico, Louisiana, Montana, West Virginia, and Wyoming all had mode shares by weight of under 50 percent for truck. Wyoming only had 5.6 percent of shipment weight transported by truck (figure 2).
Because CFS results are estimates obtained from a sample survey, the data are subject to sampling error. This report provides 90 percent confidence intervals for the estimates in tables 1, 2, 3, and 4.
The coefficient of variation (CV) of an estimate is the standard error of the estimate divided by the estimate and measures the relative sampling variability. The CV and standard error associated with an estimate can be used to construct a confidence interval. The CVs of the estimates in tables 5a to 10a are provided in tables 5b to 10b.
A confidence interval is a range around an estimate that has a specified probability of containing the average of all the estimates when samples are repeated using the same sampling frame conducted under the same survey conditions. Confidence intervals can help in assessing the reliability of estimates and in making comparisons between and among geographic areas, commodities, and modes of transportation. In other words, they help to represent the precision of an estimate and are an important reminder of the limitations of the estimates. Note that the wider a confidence interval, the less precise the estimate. Precision depends on sample size and sample variability.
For example, the value of shipments originating in Alabama in 2007 was $182.8 billion. The corresponding 90 percent confidence interval around that estimate gives the range of $155.4 billion to $210.1 billion (For more information regarding confidence intervals see Appendix B).
1 Auxiliary establishments are those specifically involved in warehousing and storage or as corporate, subsidiary, and regional managing offices.
2 The South region includes Alabama, Arkansas, Delaware, Florida, Georgia, Kentucky, Louisiana, Maryland, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, Virginia, West Virginia, and the District of Columbia.
3 The Northeast region includes Connecticut, Maine, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, and Vermont.
4 The West region includes Alaska, Arizona, California, Colorado, Hawaii, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, and Wyoming.