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Disaggregation of Freight Flows for Tennessee

Proposal Summary and Objectives

As freight transportation draws ever increasing attention in the 21st century, freight related data (e.g., commodity flows, truck flows, freight facility economic and establishment data) are becoming critical to conducting transportation planning at state, regional, and local jurisdictional levels and for corridors. The purpose of using commodity flow data is to understand which industries generate the most demand by mode on the transportation system and how to divert movement of certain commodities between various modes optimize freight flows and the use of the existing transportation network. These data provide a key link between economic trade relationships and freight demand and are used in modal diversion studies. Currently, there are several useful commodity flow data sources (open source and proprietary) at the national level. However, their application is limited to state, regional and local planning because they lack the appropriate geographic detail for flow origins and destinations. Many of the commodity flow data sources and survey techniques do not track cargo movements in a set of linked modal transfers from point of production of a product to point of consumption. This does not directly align with the desire of many state DOTs and MPOs who want to use commodity flow data for mode diversion to study their impact on specific highways or rail lines, and as the primary freight demand input to travel demand models. Commodity flow data often do not explicitly account for intermediate handling of cargo in specifying origins and destinations, and further mode specific information is not attached to the commodity flow data. Research is needed to collect, process, prepare, and develop commodity flow data for the state of TN at various aggregation levels. TDOT, and regional agencies can utilize commodity flow data to (1) better understand movement of freight and to plan ahead to provide the adequate infrastructure to meet the growing needs of freight demand, (2) use in the travel demand model for planning and forecasting, (3) maintain a database of intra and inter regional commodity flows to obtain growth and to further enhance policy decision-making such as freight diversion, and (4) develop and analyze links between commodity flows, economic activity and land use. The proposed research has the following objectives:

1. Collect and compile a geodatabase with all the available freight flow data (open source and/or proprietary) for the state of TN. In the case of proprietary data, sample data will be used if these data are not purchased by TDOT;
2. Develop the methodology and tools that can be used to estimate or disaggregate freight flow data;
3. Apply the developed methodology and tools to estimate and analyze freight flows in the State of TN at different disaggregation levels (e.g., TAZ and ZIP code level);
4. Develop a comprehensive guidebook for the estimation of commodity flows at a disaggregate level.

Funding Amount: $84,254
Status: Complete
Duration: Nov. 12, 2018 - Jan. 12, 2020

Final Report