U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
202-366-4000
Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations
REPORT |
This report is an archived publication and may contain dated technical, contact, and link information |
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Publication Number: FHWA-HRT-12-058 Date: November 2012 |
Publication Number: FHWA-HRT-12-058 Date: November 2012 |
Some of the technical details of the electronic files containing LTPP ancillary information include the following:
Electronic data formats follow U.S. National Archives and Records Administration (NARA) standards existing at the time the various versions of LTPP directives on the subject were written. In some cases, other popular formats were used if NARA did not have an existing standard at the time.
Scanned paper data forms are saved in a black and white portable document format (PDF).
Videos are digitized to moving pictures expert group (MPEG) formats.
Still images are digitized to joint photographic expert group (JPEG) formats.
File naming conventions are documented in appendix A. The file names are linked to a defined directory storage structure. Many file names contain only a survey date since they are stored in a directory storage structure that defines the type of data, the agency in which a test section is located, and the test section number. In other cases, a more complex naming scheme is used to store similar data in a common end folder location. Data users should request electronic ancillary information in the predefined folder structure shown in appendix A.
While some of the file name extensions conform to modern electronic file name practice (e.g., ".pdf" is a PDF file), many file extensions conform to LTPP practice for its custom electronic file structures. These file name extension practices change over time.
The schema that describes custom LTPP electronic data files is available upon request from LTPP CSSC.