In 2001 TRB published NCHRP Report 450: Transportation Research Thesaurus and User's Guide. The primary purpose of the Transportation Research Thesaurus (TRT) is to provide a common vocabulary for producers and users of TRB's TRIS database. Indexers can describe documents in a consistent way, and TRIS users can successfully retrieve TRIS records in their areas of interest by searching the thesaurus terms.

In addition to TRB, other organizations are using the TRT in a variety of applications and platforms: the National Transportation Library Digital Library catalog; the library catalog at the Harmer E. Davis Transportation Library, University of California, Berkeley; the library catalog of the Turner-Fairbank Highway Research Center; and the publications catalog of the Texas Transportation Institute. Moreover, the TRT vocabulary is mapped to other standard vocabularies, including the Library of Congress List of Subject Headings and the International Transport Research Documentation Thesaurus. The TRT has been approved by the Library of Congress as a specialized vocabulary with the code "trt."

Although TRB has successfully implemented use of the thesaurus, it has not had the resources to assume maintenance of the authoritative version, which resides only with the original contractor, CDB Enterprises. A thesaurus by its nature is a dynamic document to which new terms must be added as they arise. Maintenance is no small matter, and TRB should have the authoritative version of its valuable resource in-house. The proposed project would allow TRB to develop a database to maintain the authoritative version of the TRT and also to fully integrate it with the new TRIS system that TRB is developing.

Another issue is making the thesaurus more readily available to potential users. The current mechanism for distribution is the Viewer software that was developed by CDB Enterprises in 1994/95 to be compatible with the Windows environment at that time. Although the Viewer functions under Windows XP, the interface is not optimal, and distribution of files to individual PCs is cumbersome. The proposed project would support the development of a web-based version of the thesaurus that would not need to be installed and that could be updated more frequently than the Viewer.

The Transportation Research Thesaurus was developed in accordance with the principles of the Guidelines for the Construction, Format, and Management of Monolingual Thesauri (ANSI/NISO Z39.19-1993), an American national standard developed by the National Information Standards Organization and approved August 30, 1993, by the American National Standards Institute. The standard specifies equivalence (synonymous), hierarchical and associative relationships among terms and recommends print and screen formats to show these relationships. Procedures for maintaining the intellectual content of the TRT are detailed in Transportation Research Thesaurus and User's Guide. The standards and procedures should guide development of the proposed products.

Trends regarding increasing usage of the Internet are documented by the Pew Internet and American Life Project (https://www.pewinternet.org/trends.asp#usage). Such trends support the notion of moving from use of specialized software to display the thesaurus to use of a web browser.

The objectives of this study were: (1) to develop a database at TRB that a) will allow TRB to maintain the authoritative version of the TRT in-house and b) will integrate the TRT with the new TRIS system for record creation, and (2) to publish the TRT on the Internet. The tasks were as follows:

1. Develop the database structure for importing the thesaurus files.
2. Import the current database files.
3. Integrate the thesaurus database tables with the new TRIS database tables.
4. Develop a user interface for indexers to use in assigning TRT terms to TRIS records.
5. Publish a web-based version of the TRT that incorporates the screen displays (alphabetical, permuted, hierarchical, term detail) specified in the standard cited above.
6. Maintain the thesaurus software for one year after completion of Tasks 1-5.
7. Maintain/update the thesaurus vocabulary during the period of the study.