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Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590

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Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations

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Data Collection




Computed Parameters

Computed parameters are engineering parameters or summary statistics derived from the raw LTPP data, e.g., IRI (derived from longitudinal profile data), various rut indices (derived from transverse profile data), or backcalculated moduli (derived from pavement deflection data and supplemented by pavement cross-section information. The availability of computed parameters will expedite and improve the efficiency of many future analysis projects.



  • AASHTO - AASHTO Publications Department, 1-800-231-3475.

  • LTPP Customer Support Services - ltppinfo@dot.gov; (202) 493-3035.

  • R&T Report Center - 9701 Philadelphia Court, Unit Q, Lanham, MD 20706; Phone: (301) 577-0818, Fax: (301) 577-1421.

  • NTIS - National Technical Information Services, 5285 Port Royal Road, Springfield, VA 22161; (703) 605-6000. Include the PB number in the request.

  • TRB Bookstore - Transportation Research Board Bookstore, http://www.nationalacademies.org/trb/bookstore/; (202) 334-3214.



Office of Infrastructure R&D Links

» Office of Infrastructure R&D
» Infrastructure R&D Program
»Long-Term Bridge
  Performance Program

»Long-Term Pavement
  Performance Program
» Infrastructure R&D Experts
» Infrastructure R&D Laboratories
» Infrastructure R&D Projects
» Infrastructure R&D Publications
» Infrastructure R&D Topics


LTPP Email Distribution List

» Contact LTPP Customer Support Service Center at ltppinfo@dot.gov if you would like to be added to our email distribution list for LTPP Newsletters and other announcements.


FHWA Pavement Links

» Design
» Construction
» Preservation
» Maintenance
» Management
» Rehabilitation


More Information



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» Customer Service
Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000
Turner-Fairbank Highway Research Center | 6300 Georgetown Pike | McLean, VA | 22101