NEMS Freight Transportation Module Improvement Study
Release date: February 3, 2015
The U.S. Energy Information Administration (EIA) contracted with IHS Global, Inc. (IHS) to analyze the relationship between the value of industrial output, physical output, and freight movement in the United States for use in updating analytic assumptions and modeling structure within the National Energy Modeling System (NEMS) freight transportation module, including forecasting methodologies and processes to identify possible alternative approaches that would improve multi-modal freight flow and fuel consumption estimation.
IHS identified primary issues with EIA's NEMS freight transportation module with respect to state-of-the-art modeling, organized a workshop of experts to discuss alternatives to improving the NEMS transportation module, and performed independent research to ascertain improvements to the NEMS model structure. Based on the input from EIA, external experts, and further research, the final report from IHS makes the following recommendations:
- Replacing the use of the Commodity Flow Survey records with Freight Analysis Framework freight flow records as part of the ton-mile historic and projection metric development
- Application of a basic network assignment using geographic information system (GIS) estimation of truck ton-mile shares across census divisions and commodity groups
- Disaggregation of industry classifications used in NEMS to the Standard Classification of Transported Goods (SCTG) level
In addition, IHS recommended study of other issues but did not otherwise recommend immediate action:
- Exploring the potential of creating a multi-modal component to NEMS freight transportation module
- Determining if other mode-split models can be leveraged
- Study how major shifts in the economy and industry technology and management practices affect forecasts of ton-miles
EIA is now using the Freight Analysis Framework in place of the Commodity Flow Survey in the determination of historical census division and commodity ton-mile data, including the derivation of the ton-mile per dollar of industrial output (a key metric used in the travel demand projection methodology). Further, these data include a GIS modeling estimation of the share of freight truck travel between origin and destination points through intermediate census divisions. EIA expects to explore disaggregation of industry into SCTG categories in the future.
EIA will take close note of the potential for creating a multi-modal component to NEMS freight transportation module as recommended, as well as continuing to monitor and understand the changing nature of the economy and industry. IHS did not offer any recommendation on the outstanding issue of modeling the declining historical ton-miles in domestic marine shipping.