The Transportation Research Thesaurus (TRT) is a tool to improve the indexing and retrieval of transportation information. The thesaurus covers all modes and aspects of transportation. The TRT's purpose is to provide a common and consistent language between producers and users of transportation information.
The TRT Web page allows for searching and browsing the thesaurus in various formats. Click on a thesaurus term to retrieve the "family" relationships (broader, narrower, and related terms). Click on the terms alpha code to retrieve the hierarchical display for the word.