Established in 1998 by the Transportation Equity Act for the 21st Century (TEA-21), the National Transportation Library (NTL):
NTL’s initial services consisted of serving as a digital library of full-text documents, virtual reference services, and support for the National Transportation Knowledge Network (NTKN).
Its authorized role was expanded in 2012’s Moving Ahead for Progress in the 21st Century (MAP-21) which mandated NTL:
The Bureau of Transportation Statistics, part of the Office of the Assistant Secretary for Research and Technology of US DOT, administers the National Transportation Library. From 2013, NTL has been the centerpiece of US DOT’s response to the White House Office of Science & Technology Policy’s (OSTP’s) memorandum, Increasing Access to the Results of Federally Funded Scientific Research link to document. NTL's digital repository ROSA P serves as archive and point of access for US DOT-funded research.
On October 1, 2020, the NTL took responsibility for management of the DOT Headquarters Library with costs reimbursed by the DOT operating administrations. Public documents in the physical collection are being digitized and incorporated into the NTL repository. The NTL maintains access for DOT employees to interlibrary loan services and proprietary reference services formerly provided by the headquarters library. DOT employees may access these services through the DOT intranet link to site.