Although the supply chain model modeled here consisted of warehousing, transportation, and retailing operations from U.S. based organizations, the model's architecture allows it to interpreted as if it were describing a larger domestic and international system. Particularly, upstream supply chain operations including multi-modal transportation could potentially be addressed by its attribution-based nature in the form of a multi-echelon version of the model.
Fundamental sources of information to undertake such an expansion might include: the North American Industry Classification System based on Transportation Modes (1995); the Commodity
Flow Survey jointly developed by the U.S. Department of Transportation (2010b); the Waterborne Commerce Database from the U.S. Army Corps of Engineers (2009); and the Airborne Export
Network Database jointly developed by the Bureau of Transportation Statistics (BTS) (2011) among others.