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Freight Analysis Framework Version 4 (FAF4) Frequently Asked Questions

1. What is the difference between the Freight Analysis Framework (FAF) and the Commodity Flow Survey (CFS)?

The CFS primarily covers the mining, manufacturing, and wholesale sectors. FAF is comprehensive and integrates additional data to estimate volumes of shipments from industries that are not covered by the CFS, including foreign trade. The CFS provides the building blocks for the FAF:

  • Seventy percent of FAF4 freight flows by value are directly from the CFS;
  • Definitions for FAF’s 132 domestic regions;
  • Standard Classification of Transported Goods (SCTG) commodity coding scheme, used at the two-digit level for FAF (there are 43 SCTG codes used in FAF); and
  • FAF mode classifications.


2. How are metropolitan areas defined in FAF4?

The geographic boundaries of the 132 domestic FAF4 regions are the same as the published regions from the 2012 CFS. The 2012 CFS regions are a hybrid of Core-Based Statistical Areas (defined by the Office of Management and Budget) and state boundaries (any single CFS region is limited to only one State). BTS and Census selected these major regional economic centers with the goal of balancing the need for wide geographic representation with the need for data of good quality. The result is a unique region delineation that includes Metropolitan Areas (including partial), state remainders, and entire states.

More information is available at the Census CFS program page.


3. Besides the Commodity Flow Survey (CFS), what other data sources are used to construct the FAF4?

Other major data sources for FAF4 include Census Foreign Trade Statistics, Economic Census data, USDA’s Census of Agriculture, Port Import/Export Reporting Service (PIERS), Vehicle Inventory and Use Survey (VIUS), National Highway Planning Network (NHPN), Highway Performance Monitoring System (HPMS), U.S. Energy Information Administration (EIA), and other industrial data.  See FAF4 documentation for more details.


4. How are FAF4 forecasts developed?

FAF4 forecasts integrate expectations for various regional, national, and global economic conditions in order to develop growth factors for estimating future freight demand by region and commodity type. This forecasting model is macroeconomic, but it accounts for relationships among industries and among regions. Additional details about how FAF4 forecasts are constructed are available in the Forecast Results Report.


5. When will FAF4 base year data be updated?

FAF4 base year (2012) data may be updated periodically as improvements are identified. Because FAF base years coincide with CFS years and the CFS is collected in years ending in 2 and 7, the next generation of FAF will be based on 2017 CFS data. CFS data processing takes up to two years after the completion of the collection period, and FAF data processing takes most of the following year, resulting in FAF5 likely becoming available in the latter half of 2020. Annual estimates built on 2012 data are currently available for years 2013, 2014, and 2015, and additional annual estimates will be released as input data become available.


6. Can FAF4 provide routing data for through-movements?

Static maps of originating and terminating truck flows at the state level are available for download from the FHWA FAF website. A further set of state maps with only pass-through traffic is also available. The publicly available FAF4 highway network assignment output file does not support isolating pass-through flows.


7. Are empty trucks included in FAF4?

Yes, as part of the process of converting tonnage to the number of trucks, FAF estimates volumes of empty trucks by commodity and truck type. The main data source for empty trucks is the 2002 Vehicle Inventory and Use Survey (VIUS).


8. Are there county-level data or data for finer levels of geography in the FAF?  

Currently, county-level data are not available in FAF4. BTS and FHWA are aware of the growing interest in having data at finer geographic levels, and we are researching the topic.


9. Is FAF3 data still available?

Yes, archived FAF3 data are available at the FHWA FAF website.


10. Is there a list of counties that make up the FAF4 domestic zones?

Yes, a list of the U.S. counties comprising FAF4 domestic regions (which are the same as the 2012 CFS areas) can be found on the Census CFS website.


11. Is there a list of countries that make up the FAF4 foreign zones?

Yes, a list of the countries comprising the eight foreign zones in FAF4 is available in Appendix D of the FAF4 User’s Guide.


12. What are the definitions of the fields in the flat files?

A data dictionary for the FAF4 origin-destination-commodity-mode (ODCM) matrix is provided in Table 5 of the FAF4 User’s Guide.  In addition, a separate data dictionary providing definitions of attributes in the network database (FAF4 output) can be found here.


13. What is the difference between current value and constant value?

Because of inflation, the purchasing power of the dollar changes from year to year. Current value (Total Current M$) of freight in FAF reflects the actual nominal-dollar values for the reported year. For example, the current values of goods for 2014 are in 2014 dollars.

Constant value (Total M$)  reflects the inflation-adjusted dollar values in FAF4 base year dollars. Since the FAF4 base year is 2012, the price of each commodity is set similar to its respective price in 2012. For example, the constant values of goods for 2014 are in 2012 dollars.

Dollar values for all years (1997-2045) are available in 2012-dollar terms in order to make comparisons easier. Current-year value data are available for years 1997-2015.


14. Is FAF4 data for a more recent year available?

Yes, annual estimates for FAF4 are available and can be accessed from the FAF4 website.


15. What is a ton-mile?

A ton-mile is the movement of one ton of freight for one mile. (It is similar to vehicle-miles travelled, or VMT.) This measure is at the shipment level, so any total flow is the sum of the individual products of distance and weight.


16. What are the uses for FAF4 Summary Statistics?

The “Summary Statistics” available on the FAF4 website are state-level summary tables in Excel format.  These tables are designed to provide illustrative examples of FAF data and to quickly provide basic state-level freight statistics.  Please note that these tables are generated using “Total Flows,” which include both domestic and foreign trade shipments moved within the U.S., and they are presented by domestic mode of transportation only.

Four sets of summary statistics are provided with each release of FAF4:

  • Weight/value for shipments within, from, and to state by mode
  • Weight/value for shipments within, from, and to state by commodity
  • Top ten commodities by weight or value shipped within, from, and to state
  • Top five trade partners by weight or value for trade leaving state

“Within” means intrastate moves, “From” is for outbound shipments moved from the given state to all other states, and “To” is for inbound shipments moved from all other states to the given state. The “From” and “To” tabulations exclude intrastate movements.


17. What is the Data Extraction/Tabulation Tool (DET)? 

The DET is a web-based tool that allows users to extract a subset of desired records from the national FAF origin-destination-commodity-mode (ODCM) matrix. The resulting output can be saved in csv file format. Data in this file can then be analyzed or processed by the user to generate statistics as needed.


18. Why is the DET not working?

For assistance or other DET support, please email