Abstract
PROJECT DESCRIPTION
The FAF3 is a FHWA freight data product which provides a national O-D matrix of commodity
flows to, from, and within the United States. FAF3 freight flows are reported in terms of both
annual tons and annual dollars of freight moved by mode of transportation. Based largely on the
2007 CFS, FAF3 utilizes domestic freight flow characteristics, geographic regions, and the
SCTG commodity coding system from CFS.
However, many freight flows were not captured by the 2007 CFS due to scope and
sample size limitations. Approximately 100,000 establishments were sampled out of some
754,000 freight moving establishments in 2007 and imports are out of scope entirely. To estimate
missing data values, the approach taken in FAF3 was to use a combination of a novel Log-linear
modeling approach (LLM) with an iterative proportional fitting (IPF) routine that also uses
additional data inputs to fill in the missing pieces. The complete FAF3 O-D–Commodity–Mode
database is made up of 131 Origins x 131 Destinations x 43 Commodity Classes x 8 Modal
categories, for annual tons and dollars. This poster illustrates how the 2007 CFS data were
integrated with several additional data sources using LLM and IPF to create a comprehensive
FAF3 national freight flow matrix.
More detailed documentation on the sources and methods utilized in the development of
FAF3 are available from the FHWA website at the following website: http://www.ops.fhwa.dot.
gov/freight/freight_analysis/faf/index.htm.