NCFRP Report 9: Guidance for Developing a Freight Data Architecture articulates the value of establishing an architecture for linking data across modes, subjects, and levels of geography to obtain essential information for decision making. Central to the architecture is a catalog of data elements currently being collected and the definitions of those elements. Lack of a sound freight data dictionary can cause problems within and across organizations, with organizations calling the same freight data element by different names or different data elements by the same name. In a worse case, an organization may combine freight data elements it thinks are equivalent and make incorrect investment decisions from invalid data.
What is needed is a data dictionary for organizing the myriad of freight data elements currently in use, a method for identifying differences in definitions and methods for bridging between definitions, and a method for assessing whether differences are appropriate or should be harmonized.
The objective of the research is to produce a searchable and sustainable web-based freight data element dictionary for transportation analysis to be hosted at the U.S. Department of Transportation’s Bureau of Transportation Statistics (BTS) (see Special Note F).
Accomplishment of the project objective will require at least the following tasks.
(1). Identify readily available databases associated with freight for inclusion in the dictionary; including their key characteristics. (2). Inventory elements used in these databases (e.g., type and level of measurement, attribute definitions, and spatial and temporal characteristics). (3). Organize and classify the elements into a typology (with rationale) across databases and provide terms and definitions used for each element, taking into account the intended uses (e.g., land use, planning, environmental impacts, economic development, supply chain analysis, safety, and security). (4). Develop and test a user interface for the searchable and sustainable web-based freight data element dictionary and make updates based on findings from the testing of the user interface.(5). Within 8 months, prepare an interim report and a contractor-hosted beta version of the searchable and sustainable web-based freight data element dictionary.
(6). Based on the results of Phase 1 and the input of the project panel, identify differences in definitions and assess whether crosswalks or other bridges are adequate and relevant. (7). Recommend new harmonization or statistical bridges as appropriate for resolving differences in definitions. (8). Prepare a production-ready, BTS-hosted searchable and sustainable web-based freight data element dictionary, full documentation (including data structures, data requirements, source code, and maintenance and updating guidelines), and a draft user’s manual. Revise based on consideration of NCFRP review and comments.(9). Three months prior to contract completion date, prepare a draft final deliverable documenting the research, a BTS-hosted searchable and sustainable web-based freight data element dictionary, a systems administrator’s guide, and a user’s manual (see Special Notes F and G).