USA Banner

Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Freight Analysis Framework Version 5 (FAF5) Experimental County-Level Estimates: Technical Report and User Guide

Friday, January 31, 2025

Overview

The Freight Analysis Framework (FAF) database provides estimates of the weight and value of shipments throughout the United States for all commodity types and forms of transportation using a geographic system of 132 FAF zones. The largest zones are entire states. The large zone size limits the useability of FAF for many applications. The user community has expressed a need for more geographically granular commodity flow data to support planning, policymaking, and operational decisions at the state and local levels. In response to this need, BTS developed an experimental county-to-county commodity flow product using publicly available data and transparent methods. This website provides a User Guide and a link to the technical documentation. BTS welcomes users to email FAF@dot.gov with feedback on this experimental product.

Technical Report

Users can download the Technical Report using the link at the top of this webpage. 

User Guide

Users can access files for this data release at https://www.bts.gov/faf/county. Data users can download two types of files: state-specific files and disaggregation factors for all counties in the U.S. Table 1 lists the five commodity groups that the release files use to refer to commodity type. The sctgG5 field contains this information. Table 2 lists the mode groups and their codes, which the state-level files use in the dms_mode field. This webpage provides a detailed explanation of these release files. The release files exclude FAF modes 7 and 8.

Table 1. SCTG Group Codes in the Disaggregation Data Products

sctgG5 Code

Definition

FAF SCTG Code

sctg0109

Agricultural products

1–9

sctg1014

Gravel and mining products

10–14

sctg1519

Coal and other energy products

15–19

sctg2033

Chemical, wood and metals

20–33

sctg3499

Manufactured goods, mixed freight, waste and unknown

34–99

Table 2. New Mode Code in the Disaggregation Factor Tables

New Mode Code

New Mode Definition

FAF Mode Code

11

Truck and Air

1—Truck

4—Air

2

Rail

2—Rail

3

Water

3—Water

5

Multiple modes and mail

5—Multiple modes and mail

6

Pipeline

6—Pipeline

 

STATE-BASED DISAGGREGATION RESULTS

The release includes 51 state-specific zip files (including one zip file for Washington, DC). Each file represents flows using county-level geography for the main state and for states adjacent to the main state. Geographic representation of flows outside of this area consists of FAF zones. Each state zip file contains four tables representing 1) county-level OD flows for the state of interest and every adjacent state, 2) county-to-FAF zone Origin-Destination (OD) flows from the multi-state area to all other FAF zones, 3) FAF zone-to-county OD flows from all other FAF zones to the multi-state area, and 4) FAF zone-to-FAF zone OD flows from all other FAF zones to all other FAF zones.

Example: Release File for the State of Maryland

Figure 1 shows the multi-state area of Maryland and its immediate area, which includes four adjacent states (Pennsylvania, Delaware, Virginia, and West Virginia) and the District of Columbia. The zip file contains:

  • Table 1: county-to-county commodity flows between all counties in this multi-state area
  • Table 2: county-to-FAF zone commodity flows from counties in the multi-state area to the FAF zones outside of this area
  • Table 3: FAF zone-to-county commodity flows from the FAF zones outside of the multi-state area to counties in the multi-state area
  • Table 4: FAF zone-to-FAF zone commodity flows between all other FAF zones outside of the multi-state area.

Figure 1. Maryland with Surrounding States and Washington, DC

Maryland with its surrounding states and Washington, DC.

Source: BTS and OpenStreetMap 2024.

DISAGGREGATION FACTORS: DESCRIPTION AND APPLICATION

The full set of county-level factors (origin and destination factors) are contained in one zip file. Users can merge these factors with FAF regional databases to create a county-level database for a customized geographic area or for the entire U.S. Users will need to download the FAF regional databases from www.bts.gov/faf. The FAF database download includes metadata with variable dictionaries. The factors are available for four modes and five commodity groups. The zip file contains files with disaggregation factors for four modes:

  • Rail (rail_origin_factors.csv and rail_destination_factors.csv)
  • Water (water_origin_factors.csv and water_destination_factors.csv)
  • Truck (truck_origin_factors.csv and truck_destination_factors.csv)
  • Pipeline (pipeline_origin_factors.csv and pipeline_destination_factors.csv)

Users can apply the truck factors to air and multiple modes and mail modes to generate county-to-county flows for these modes. This experimental product does not include methods to disaggregate flows by other or unknown mode, or flows that use no domestic mode.

Table 3 explains the variables in the origin factor files. The data structure in the destination factor file is the same. The factor files include the county FIPS code, the county’s corresponding FAF zone code, commodity group, and the disaggregation factor for that combination of county and commodity group.

Table 3. Layout of FAF Origin Factor Table

Variable name

Description

dms_orig

Origin FAF code

dms_orig_cnty

Origin county FIPS code

sctgG5

Commodity group code

f_orig

The proportion of FAF zone tons of sctgG5 that originate in this county

Users can apply the process that Figure 2 illustrates to disaggregate FAF zone flows to the county level. The steps are:

  1. (Optional) Select FAF trips for the area of interest. This will reduce the size of the input dataset, which improves efficiency in the remaining disaggregation steps. For example, to generate county-to-county tonnage estimates only for Iowa to Idaho, the user can select flows with dms_orig=190 and dms_dest=160, filtering out all other flows.
  2. Select FAF trips for the mode of interest. For example, to disaggregate rail flows, select flows with dms_mode=2 (rail) from the previous step, filtering out all other flows.
  3. Use the commodity correspondence from Table 1 to summarize the flows from the previous step (red box in Figure 1) using the five commodity groups. This will reduce the 42 commodity categories to five.
  4. Join the resulting table from the previous step to the origin factor table based on the FAF origin zone (dms_orig) and commodity group (sctgG5) columns. The resulting file now contains the factor for the origin county and commodity group (f_orig).
  5. Join the resulting table from the previous step to the destination factor table based on the FAF destination zone (dms_dest) and commodity group (sctgG5) columns. The resulting file now contains the factor for the destination county and commodity group (f_dest).
  6. The resulting table contains all possible combinations of county pairs and commodity groups that are present in the original FAF estimates for the selected area and mode. Users can calculate the final county-to-county tonnage by commodity group by multiplying the total FAF zone-level tons by the origin factor and the destination factor. The Figure 2 note shows these formulas.

Figure 2. Example: Applying Disaggregation Factors

This figure shows three data tables. The first data table is a FAF data table with four rows and with FAF domestic origin, FAF domestic destination, commodity type sctg2, and tons from year 2022. This table flows into a second table. The second table has one row and it shows the sctgG5 field and the sum of tons from the first table, indicating that tons from the first table have been summed based on the sctgG5 commodity type. This flows into the third and fourth tables, which contain the same fields as before plus new fields for the origin and destination counties and their disaggregation factors, f_orig and f_dest. These two tables flow into the last table, which now has one row for each county-to-county pair, the final factor, and the disaggregated tonnage.

Source: BTS.

Note: f = f_orig*f_dest, tons_2022_c2c = tons_2022*f

DOT is committed to ensuring that information is available in appropriate alternative formats to meet the requirements of persons who have a disability. If you require an alternative version of files provided on this page, please contact bts@dot.gov.