GENERAL

The Commodity Flow Survey (CFS) is a joint effort by the Bureau of Transportation Statistics (BTS) and the U.S. Census Bureau, U.S. Department of Commerce. The survey is the primary source of national and state-level data on domestic freight shipments by establishments in mining, manufacturing, wholesale, auxiliaries, and selected retail and services trade industries located in the 50 states and the District of Columbia. Data are provided on the type, origin and destination, value, weight, modes of transportation, distance shipped, and ton-miles of commodities shipped. The CFS is conducted every 5 years as part of the economic census. It provides a modal picture of national freight flows and represents the only publicly available source of commodity flow data for the highway mode. The CFS was conducted in 1993, 1997, 2002, 2007, and most recently in 2012.

The CFS assesses the demand for transportation facilities and services, energy use, and safety risk and environmental concerns. CFS data are used by policy makers and transportation planners in various federal, state, and local agencies. Additionally, business owners, private researchers, and analysts use the CFS data for analyzing trends in the movement of goods, mapping spatial patterns of commodity and vehicle flows, forecasting demands for the movement of goods, and determining needs for associated infrastructure and equipment.

HAZARDOUS MATERIAL SHIPMENTS

The U.S. Department of Transportation defines hazardous materials as belonging to one of the nine hazard classes, as shown below.

Hazardous Material Classes:

Class 1—Explosives
Class 2—Gases
Class 3—Flammable Liquids
Class 4—Flammable Solids
Class 5—Oxidizing Substances and Organic Peroxides
Class 6—Toxic Substances and Infectious Substances
Class 7—Radioactive Materials
Class 8—Corrosive Substances
Class 9—Miscellaneous Hazardous Materials

As part of the shipment characteristics collected in the 2012 CFS, we asked respondents to provide the four-digit United Nations (UN) or North American (NA) identification number. For the 2012 CFS data, we used the UN/NA code to: (1) identify the shipment as hazardous material, and (2) assign the shipment to one of the nine hazardous material classes for purposes of producing summary tabulations.

The data from the 2012 CFS for hazardous material shipments are aggregated to these nine classes, as well as their subcategories known as divisions. Data are also shown for selected UN/NA codes.

For the 2012 CFS, 26 Standard Classification of Transported Goods (SCTG) codes were identified as always being hazardous materials. Even if the respondent left the UN/NA code blank, we assigned the shipment to the appropriate UN/NA code. For example, every shipment of gasoline (SCTG 17110) was assigned a UN/NA code of 1203 either by the respondent or during our tabulation process. When an SCTG could have translated to more than one UN/NA code, the shipment was reviewed and the appropriate UN/NA code was chosen.

Please note that because of the industry coverage and shipment definitions of the CFS, certain hazardous materials such as infectious substances or radioactive wastes were not well represented in the CFS data.

The UN classification system has been adopted for worldwide use by the United Nations Committee of Experts on the Transport of Dangerous Goods. The UN system was incorporated into the Federal Code of Regulations by the U.S. Department of Transportation for domestic transportation in 1980. The NA system is a parallel hazard identification system used in North America when transporting hazardous materials that are not assigned a UN number or when transporting under specific North American exceptions. For additional information about the UN or NA codes, please refer to Title 49, Code of Federal Regulations, Part 172.101 or contact the Hazardous Materials Regulations Center, Research and Special Programs Administration, U.S. Department of Transportation, at telephone number 800-467-4922 or see the Internet site http://phmsa.dot.gov/hazmat

SCOPE

Industry Coverage

The 2012 CFS covers business establishments with paid employees that are located in the United States and are classified using the 2007 North American Industry Classification System (NAICS) in mining, manufacturing, wholesale, and selected retail and services trade industries, namely, electronic shopping and mail-order houses, fuel dealers, and publishers. Additionally, the survey covers auxiliary establishments (i.e., warehouses and managing offices) of multiestablishment companies.

For the 2012 CFS, a targeted Advance Survey (precanvass) was conducted in 2011 to improve the quality of the data on the frame for certain industries or types of establishments. The groups included in this advance survey were:

For the first three groups, the purpose was to identify those establishments that actually conduct shipping activities. In these groups, surveyed establishments that reported that they did not conduct any shipping activity were excluded from the eventual CFS sample universe. For large establishments the objective was to obtain an accurate measure of their shipping activity.

CFS Industries

In-scope industries for the 2012 CFS were selected based on the 2007 NAICS. Industries included in the 2007 and 2002 CFS were selected based on the 2002 and 1997 versions of the NAICS, respectively. The industries in the 1997 CFS and the 1993 CFS were selected based on the 1987 Standard Industrial Classification System (SIC) and, although attempts were made to maintain similar coverage among the SIC based surveys (1993 and 1997) and the NAICS based surveys (2002, 2007, and 2012), there have been some changes in industry coverage due to the conversion from SIC to NAICS. Most notably, coverage of the logging industry changed from an in-scope Manufacturing (SIC 2411) to the out-of-scope sector of Agriculture, Forestry, Fishing, and Hunting under NAICS 1133. Also, publishers were reclassified from Manufacturing (SIC 2711, 2721, 2731, 2741, and part of 2771) to Information (NAICS 5111 and 51223) and were excluded in the 2002 CFS. The 2007 and 2012 CFS, however, include publishers and retail fuel dealers.

The (2007) NAICS industries covered in the 2012 CFS are listed in the following table:

¹ Excludes Prepress Services (NAICS 323122). ² Wholesale establishments exclude manufacturers sale offices and own brand importers. ³ Includes only captive warehouses that provide storage and shipping support to a single company. Warehouses offering their services to the general public and other businesses are excluded. NAICS 4841 and 4842 are new industries to the 2012 CFS. For tabulation and publication purposes, NAICS 484 is grouped with NAICS 4931. ⁴ In 2007, NAICS 51223 Music Publishers was tabulated and published in NAICS 5111. However, for the 2012 cycle, NAICS 51223 was not sampled. ⁵ Includes only those establishments in NAICS 551114 with shipping activity. Notes: Excluded industries: Foreign establishments, establishments classified in transportation, construction, and most retail and services industries are excluded. Other industry areas that are not covered, but may have significant shipping activity, include agriculture and government. For agriculture, specifically, this means that the CFS does not cover shipments of agricultural products from the farm site to the processing centers or terminal elevators (most likely short-distance local movements), but does cover the shipments of these products from the initial processing centers or terminal elevators onward. General exclusions: Data for government-operated establishments are excluded from the CFS. These include public utilities, publicly operated bus and subway systems, public libraries, and government-owned hospitals. The CFS also excludes establishments or firms with no paid employees.

Shipment Coverage

The CFS captures data on shipments originating from select types of business establishments located in the 50 states and the District of Columbia. The CFS does not cover shipments originating from business establishments located in Puerto Rico and other U.S. possessions and territories. Likewise, shipments traversing the United States from a foreign location to another foreign location (e.g., from Canada to Mexico) are not included, nor are shipments from a foreign location to an initial U.S. location. However, imported products are included in the CFS from the point that they leave the importer’s initial U.S. location for shipment to another location.

Shipments that are shipped through a foreign territory with both the origin and destination in the United States are included in the CFS data. The mileage calculated for these shipments exclude the foreign country segments (e.g., shipments from New York to Michigan through Canada do not include any mileage for Canada). Export shipments are included, with the domestic destination defined as the U.S. port, airport, or border crossing of exit from the United States. See the Mileage Calculation section for additional detail on how mileage estimates were developed.

Data Collection

Each establishment selected into the CFS sample was mailed a questionnaire for each of its four reporting weeks, that is, an establishment was sent a questionnaire once every quarter of 2012. For a given establishment, the respondent was asked to provide the following information about each of the establishment’s reported shipments:

• Shipment ID number
• Shipment date (month, day)
• Shipment value
• Shipment weight in pounds
• Commodity code from Standard Classification of Transported Goods (SCTG) list
• Commodity description
• An indication of whether the shipment was temperature controlled
• United Nations or North American (UN/NA) number for hazardous material shipments
• U.S. destination (city, state, zip code)—or gateway for export shipment
• Modes of transport
• An indication of whether the shipment was an export
• City and country of destination for exports
• Export mode

By CFS definition, a shipment is a single movement of goods, commodities, or products from an establishment to a single customer or to another establishment owned or operated by the same company as the originating estab-lishment (e.g., a warehouse, distribution center, or retail or wholesale outlet). Full or partial truckloads were counted as a single shipment only if all commodities on the truck were destined for the same location. For multiple deliveries on a route, the goods delivered at each stop were counted as one shipment. Interoffice memos, payroll checks, or business correspondence were not included in the CFS. Likewise, the CFS does not include shipments of refuse, scrap paper, waste, or recyclable materials unless the establishment was in the business of selling or providing these materials.

For a shipment that included more than one commodity, the respondent was instructed to report the commodity that made up the greatest percentage of the shipment’s weight.

In addition, establishments were asked to provide informa-tion about the use and extent of rush delivery services.

Data Collection Method

The CFS survey was conducted through a mailout/mailback with an electronic reporting option. Each establishment selected into the 2012 CFS sample was mailed four ques-tionnaires—one during each calendar quarter of the year 2012. The four questionnaires were the same for all report-ing periods (see Appendix E for a copy of the question-naire). The establishments were asked to provide shipment information about a sample of their individual outbound shipments during a prespecified one-week period in each calendar quarter. Each of the 4 weeks was in the same relative position of the calendar quarter. Respondents had the option of reporting electronically and were given log-in information on their mailed questionnaire.

Mileage Calculations

General

The distance traveled by each freight shipment reported by the respondents to the 2012 CFS was estimated by a soft-ware tool called GeoMiler that uses routing algorithms and an integrated, intermodal transportation network that has been developed and updated expressly for this purpose. Each shipment record contained the ZIP Codes of shipment origin and destination (O-D pair) and the mode or modal sequence required by the routing algorithm for distance estimation. Each record also contained information on type of commodity moved, its weight, dollar value, and hazardous materials (hazmat) status. For each export ship-ment, the U.S. port of exit (POE) was also identified, along with foreign destination country; a destination country of Canada/Mexico also required a Canadian/Mexican destina-tion city.

Valid and accurate O-D pair ZIP Codes were essential elements needed for estimating the travel distance of any shipment. For shipments with missing or invalid geographic data elements, such data elements were imputed, if a reasonable correction appeared obtainable (e.g., if a specific destination city/state was provided, then a “reasonably reliable” destination ZIP Code was imputed for the shipment). Follow-up contact with respondents was required when the missing information could not be reasonably imputed.

GeoMiler—Software to Measure the Distance Traveled by Commodity Shipments

The CFS does not ask respondents to report the distance traveled for each shipment. Therefore, shipment mileage was calculated using GeoMiler, a routing tool developed by BTS specifically for CFS mileage calculations. GeoMiler used current Geographic Information System (GIS) technology and spatial multimodal network databases and integrated map-visualization features with route solvers to handle many alternative multimodal combinations. This tool used algorithms that found the quickest path over spatial representations of the U.S. highway, railway, waterway, and airway networks. For waterborne export shipments, GeoMiler used a waterborne commerce database from the U.S. Army Corps of Engineers (USACE) to route freight originating in the United States via the deep sea (ocean). For airborne export shipments, GeoMiler used an updated air export network from the BTS Office of Airline Information (OAI).

Methodological Changes to Mileage Calculation for the 2012 CFS

With a valid origin and destination Zip Code, GeoMiler will calculate the distance traveled (in miles) by mode for each shipment reported in the CFS. The following types of methodological changes to mileage processing were incorporated in 2012:

• A shipment with a respondent-provided mode of Parcel must weigh 150 pounds or less; in addition, a shipment with a respondent-provided mode of Air was not given a weight restriction.
• A mode of transportation was imputed whenever a respondent provided a mode of Other, or Unknown, or otherwise failed to provide a modal response (missing mode) for a shipment.
• Private truck is considered a “short-haul” mode; hence Private truck shipments were not routed more than 500 miles during shipment routing.

Air Versus Parcel Mode

According to the 2007 CFS Instruction Guide, an Air shipment was defined as a shipment that weighed 100 pounds or more. During mileage processing for the 2007 CFS, an Air shipment was manually converted to Parcel if the weight of the shipment was less than 100 pounds.

However, airlines do not necessarily have minimum weight restrictions when transporting cargo. Hence, for the 2012 CFS, the definition of an Air shipment was changed. As a result, an Air shipment was acceptable as provided by the respondent, regardless of weight.

Furthermore, for the 2012 CFS, Parcel shipments conformed to the definition used by the parcel industry that a parcel is a shipment of 150 pounds or less. For shipments submitted by the respondent with mode of Parcel and a weight above 150 pounds, GeoMiler changed the mode to For-hire truck during mileage processing.

Routing a Shipment When Mode Is Other, Unknown, or Missing

On the survey form, respondents were given the following choices for mode of transport: Air, Highway (Private truck or For-hire truck), Rail, Waterway (Inland water or Deep sea), Parcel, Pipeline, Other mode (meaning none of the above), or Unknown.

During the 2007 CFS mileage processing, 2.4 percent of shipments had a respondent-provided mode of Unknown or Other, and an additional 2.1 percent had no reported mode at all. In these situations, the mode of transport was imputed. For 2012 CFS mileage processing, if the shipment weighed less than 80,000 pounds, it was routed via Highway mode as For-hire truck; if the shipment weighed 80,000 pounds or more, it was routed via Rail mode.

Private Truck Versus For-Hire Truck

Shipments via Private truck are generally “short-haul” in nature. Because of the number of shipments exceeding this norm in the 2007 CFS, Census Bureau analysts researched the Private truck shipments at or above 500 miles. In almost all cases, the mode should have been reported as For-hire truck instead of Private truck.

Consequentially, for 2012 CFS GeoMiler mileage processing, Private truck was converted to For-hire truck if the shipment mileage was equal to or greater than 500 miles, regardless of the commodity being transported. The 2012 CFS preliminary data shows a decrease from 2007 in average miles per shipment for Private truck, with an average of 46 miles per shipment.

Mileage for Domestic Shipments

For a domestic shipment, the mileage was calculated between the centroid (center of a geographic area) of the U.S. origin ZIP Code and the centroid of the destination ZIP Code. The route between an O-D pair was composed of a series of links, and an impedance factor was assigned to each link (impedance is defined as a function of distance and travel time). Given a mode or modal sequence, the role of GeoMiler was to find that “best path” route which minimized the total impedance of the links between the specified O-D pair.

The mileage for shipments within a ZIP Code (matching O-D pair) was calculated by means of a formula that approximated the longest distance within the boundaries of that ZIP Code.

For multimodal shipments (those shipments involving more than one mode, such as truck-rail shipments), spatial joins (intermodal transfer links) were added to the network database to connect the individual modal networks together for routing purposes. An intermodal terminals database and a number of terminal transfer models were developed at BTS to identify likely transfer points for freight. An algorithm was used to find the minimum impedance path between a shipment’s origin ZIP Code to the transfer point and then from the transfer point to the destination ZIP Code. Thus, for multimodal shipments, the cumulative length of the spatial joins, plus links on the path, was used for estimating distances.

To estimate highway mileage, GeoMiler considered the functional class of highway so that the “single best path” was the quickest path based on the likely use of interstate and other major roadways and not necessarily the shortest path. The “quickest path” algorithms in terms of travel time incorporated the following hierarchical functional class of highway:

1. Interstate route
2. U.S. route
3. State route
4. County or other local route

The model favored the selection of higher-order routes (interstate) rather than lower-order routes (state and county), which provided a more realistic path for freight movement via highway.

To estimate railway mileage, GeoMiler selected a “single best path” from those calibrated with route density information obtained from sampled rail waybills, assigned a specific railroad company at shipment origin, and considered ownership, trackage rights, and interlining (the transfer from one railroad company’s trackage network to that of another).

To estimate waterway mileage, GeoMiler selected a “single best path” from the USACE waterway network featuring dock-to-dock movements (from the dock nearest to origin, to the dock nearest to destination) by specific two-digit commodity codes for the Standard Classification of Transported Goods (SCTG).

To estimate domestic airway mileage, GeoMiler selected the “single best path” from the three airports closest to the origin ZIP Code to the three airports closest to the destination ZIP Code. Criteria for route selection were calibrated with air route information provided by the OAI at BTS. As in the past, to be acceptable, an airway routing must generate at least twice as many airway miles as highway miles (the ratio of air/truck miles should be at least 2 to 1) in order to reach the destination. Consequently, GeoMiler chose the most likely air route from those routes that were nonstop (direct) from airport facilities with higher cargo lifts (weight transported between two airports) based on the OAI air cargo data.

Mileage for Pipeline Shipments

For pipeline shipments, ton-miles and average miles per shipment are not shown in the data files. For most of these shipments, the respondents reported the shipment destination as a pipeline facility on the main pipeline network. Therefore, for the majority of these shipments, the resulting mileage represented only the access distance through feeder pipelines to the main pipeline network and not the actual distance through the main pipeline network. Pipeline shipments are included in the U.S. totals for ton-miles and average miles per shipment. For security purposes, there is no pipeline network available in the public domain with which to route petroleum-based products. Hence, any modal distance, either single or multi, involving pipeline was considered as solely pipeline mileage from origin ZIP Code to destination ZIP Code and calculated to equal great circle distance (GCD). GCD is defined as the shortest distance between two points on the earth’s surface, taking into account the earth’s curvature.

Mileage Routing in Alaska

Much of Alaska is inaccessible by any mode of transportation except “bush” airplanes. A “bush” airplane is a small aircraft that usually carries no more than four people, including the “bush” pilot. For the 2012 CFS, a network of mini airports, more extensive than that used previously in the 2007 CFS, was incorporated into intrastate travel within Alaska to accommodate “short-hop” flights where no established roads existed, especially in cases where the respondent reported a mode of highway.

Mileage for Export Shipments

For all exports, GeoMiler determined a U.S. port of exit (POE): seaport, airport, or border crossing (in the case of highway exports to the border countries of Canada/Mexico). However, only the portion of mileage measured within U.S. borders was included as domestic mileage in the CFS estimates for export shipments. To find the POE, GeoMiler used foreign destination country, type of commodity being exported, port volume (tonnage), and domestic travel distances.

The mileage estimates for export shipments in the 2012 CFS included the total distance from the shipment origin up to the exit point on the U.S. territorial borders.

For waterway exports via inland waterways (e.g., the Mississippi River), the mileage calculation included the distance from an inland water POE (such as St. Louis) to a coastal POE (such as New Orleans), and this extra inland waterway mileage was included in the total domestic mileage for this shipment.

For waterway exports via the Great Lakes (Lakes Erie, Huron, Michigan, Ontario, Superior), the mileage calculation was continued from a Great Lakes POE (such as Chicago, Cleveland, Duluth) to the line of demarcation between the United States and Canada (drawn within each of the Great Lakes except Michigan), and this extra Great Lakes mileage was included in the total domestic mileage for this shipment.

For airway exports, the total domestic mileage included the mileage from the inland POE to a coastal point on the U.S. landmass (where the air flight path to a foreign country intersected with the U.S. territorial border).

Availability of Additional Transportation Data

Users of transportation data may be especially interested in the reports from the Service Annual Survey, which can be found on the Census Bureau’s Web site at www.census.gov/services This survey covers firms with paid employees that provide commercial motor freight transportation and public warehousing services. Data collected include operating revenue and operating revenue by source, percentage of motor carrier freight revenue by commodity type, size of shipments handled, length of haul, and vehicle fleet inventory.