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Publication Number:  FHWA-HRT-21-099    Date:  Summer 2021
Publication Number: FHWA-HRT-21-099
Date: Summer 2021
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Cartoon depicts a roadway under contruction nect to a building. The Building has two visible offices labeled "Data Analysis" and "Data Base." On the roadway, there are labels reading "Climate Data," "Materials," "Profile," "Deflection," "Drainage," "Distress," "Traffic," and "Forensics."   LTPP


Value in Conducting Forensic Investigations

The Long-Term Pavement Performance (LTPP) program has long considered forensic investigations to be of great value, not only for examining and explaining distress causes and mechanism(s), but also for explaining what worked and why (i.e., the performance of test sections).

In support of the LTPP program, Transportation Pooled Fund Study TPF-5(332), "Performing Forensic Evaluations of LTPP Remaining Sections Before They Leave Service," was established in 2017 to investigate LTPP test sections as they are scheduled to go out of service, capturing data on exactly why the pavements performed as they did. The Washington State Department of Transportation (WSDOT) managed the study, and financial support was provided by WSDOT, the California, Mississippi, New York, and Texas departments of transportation (DOTs), and the Federal Highway Administration (FHWA).

The figure shows a map of the locations in the United States where test sections were investigated. A total of 63 test sections in 23 States (Arizona, Colorado, Kansas, Ohio, Mississippi, California, Florida, New Mexico, Iowa, Montana, Georgia, South Carolina, Maine, Utah, Maryland, Indiana, Minnesota, Pennsylvania, Arkansas, Idaho, Washington, Texas, and Oklahoma) are marked on the map. © 2021 WSDOT.
Figure 1. Map. Geographical location of forensic investigation sites.1

When the pooled fund study began in 2017, there were approximately 750 active LTPP test sections. By the time the study was completed in June 2021, forensic evaluations had been conducted on 63 test sections at 26 different locations in 23 different States. The location of these test sections and their climatic distribution are shown in figure 1 and figure 2, respectively.

The figure depicts a pie chart showing the distribution of the TPF-5(332) forensic investigations by climate. The pie chart shows 42 percent of the investigations were in wet, freeze climates; 23 percent were in wet, no-freeze climates; 19 percent were in dry, freeze climates; and 16 percent were in dry, no-freeze climates.  © 2021 WSDOT.
Figure 2. Chart. Climatic distribution of forensic investigation sites.2

The forensic pooled fund study provided important benefits to the participating DOTs, including understanding the factors that produce good or poor performing pavements and how LTPP data can be used to benefit the State's pavement engineering operations. The study also demonstrated how a forensic investigation could advance the State's pavement engineering practices. The study provided the added benefit of reviewing the adequacy of the data in the LTPP database to explain the performance of the test sections. In addition, the study yielded many important findings that contributed to improving the LTPP data in terms of both completeness and quality.

For example, core measurements taken at the California 067452 test section (figure 3) showed the layer structure for the latest construction event to be incorrect. This finding, along with others, was discovered during interviews and meetings with the appropriate DOT staff to better understand the performance of the test sections. The technical memoranda and quarterly reports resulting from these investigations and other information for this study can be found on the Transportation Pooled Fund website.

This figure shows a photograph of a core taken at California LTPP test section 067452 on February 19, 2020. The core has been positioned horizontally such that the top of the core is to the left in the photograph and the bottom of the core is to the right. A crack is shown across the sample and numbers and two left-pointing arrows are written on the sample. © 2021 WSDOT.
Figure 3. Photograph. 2020 core from California test section 067452.3

At present, approximately 336 active test sections in 31 States remain in the LTPP program. Given the benefits to LTPP stakeholders and the program derived from the conduct of the forensic investigation of test sections being phased out of study, especially in terms of data completeness and quality, it is important that the forensic investigation work continue. Efforts are underway to establish a new pooled fund study to carry out these investigations on the remaining LTPP test sections. Test sections that are no longer active but have remained unchanged will also be considered for investigation. State DOTs are strongly encouraged to join and actively participate in this new study.

For further technical information, see solicitation 1560, posted on the pooled fund website, or contact Deborah Walker of FHWA at deborah.walker@dot.gov or Mustafa Mohamedali of WSDOT at mohamem@wsdot.wa.gov.

FHWA Launches a New Knowledge Web Portal

The Long-Term Infrastructure Performance (LTIP) team and FHWA's Nondestructive E valuation (NDE) program are excited to announce the launch of FHWA InfoTechnologyTM!

InfoTechnology is a knowledge Web portal that helps practicing transportation engineers, university students, and others learn about NDE technologies used to assess highway infrastructure components.

This figure is a screen capture of the homepage for the FHWA InfoTechnology Web portal. The homepage includes three main navigation tiles (bridge, pavements, and tunnel) with corresponding infrastructure photographs as backgrounds. Users can access information on applicable Nondestructive Evaluation (NDE) technologies based on the selected infrastructure type. A menu bar is located at the top of the homepage, which provides users with access to the InfoTechnology Library hub. A Customer Support link is in the upper right-hand corner of the homepage. Source: FHWA.
Figure 4. Screenshot. FHWA InfoTechnology.

In the past, some of you may have explored the FHWA NDE Web manual. InfoTechnology offers a completely new design of the user interface and expands the content of the NDE Web Manual to include NDE technologies for bridges, pavements, and tunnel components. In the future, the LTIP team and FHWA's NDE program plan to enhance the portal and incorporate structural health monitoring technologies and other features.

Please explore and share the InfoTechnology Web portal link with your colleagues. For more information, contact Hoda Azari at hoda.azari@dot.gov.

  1. WSDOT. TPF-5(332) Performing Forensic Evaluations of LTPP Remaining Sections Before They Leave Service. Olympia, WA: WSDOT.
  2. WSDOT. TPF-5(332) Performing Forensic Evaluations of LTPP Remaining Sections Before They Leave Service. Olympia, WA: WSDOT.
  3. Rada, G., G. Elkins, N. Weitzel, and K. Senn. 2020 (revised). Forensic Desktop Study Report: California LTPP Test Section 06_7452. Technical Memorandum. Beltsville, MD: Wood Environment & Infrastructure Solutions, Inc.

In Brief

LTPP Standard Data Release 35 Now on LTPP InfoPaveTM

Pavement performance, traffic, construction, and other data collected under the FHWA LTPP program are released every year in the form of a Standard Data Release (SDR). The 35th release of LTPP data is now available on LTPP InfoPave. For this release, the dataset was updated to include performance data collected in 2020. Significant new materials testing for the warm-mix asphalt overlay experiments (SPS-10) were added. The National Aeronautics and Space Administration's Modern-Era Retrospective Analysis for Research and Applications (MERRA) climate data were updated to include 2020 MERRA-2 data, keeping this important dataset current.

In addition to these data updates, highlights of the website functionality improvements included upgrading the search capabilities to return more relevant results. The LTPP Data Analysis Plan has been restructured and reorganized into five new objectives to replace the previous nine objectives. The new project statements from the LTPP Data Analysis Workshop were added. The results from the workshop are documented in a TechBrief entitled, Long-Term Pavement Performance Data Analysis Plan. The temperature output for LTPPBind Online has been reconfigured and updated to improve the accuracy of the tool.

The LTPP program continues to increase the amount of data it releases annually to the public and improve the quality assurance process used to verify these data as needed. See the LTPP SDR Release Notes for changes in data and the LTPP InfoPave Release Notes for specific additions and changes to the InfoPave Web portal.

FHWA InfoMaterialsTM Dataset Management TechBrief Released

FHWA collects a tremendous amount of valuable data through cutting-edge testing technology, sponsored research, and other collaborative efforts. Data are essential for research and innovation, so it is crucial that FHWA preserve, document, and provide accessibility to stakeholders and researchers to reduce data collection duplication and maximize the benefits of the collected data. FHWA's LTIP team recently developed and published a TechBrief entitled FHWA InfoMaterialsTM Dataset Management to facilitate this process. Researchers can use the contents of this TechBrief to format their data in a manner that is intuitive and reusable by other researchers.

The TechBrief provides information about data organization and storage in terms of data types, metadata, formats, and organization.

Examples of the organization of different kinds of data are included for illustrative purposes.

If you have any data management questions, contact Jane (Yan) Jiang at jane.jiang@dot.gov.

Student Contest Papers Received

This year's Student Data Analysis Contest closed on July 30. Papers are being reviewed, and winners will be announced in November.

New Publications


FHWA InfoMaterialsTM Dataset Management FHWA-HRT-21-065 [PDF]
Long-Term Pavement Performance Data Analysis Plan FHWA-HRT-20-023 [PDF]

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Recommended citation: Federal Highway
Administration, Traffic Management Center
Pooled Fund Study (Washington, DC: 2021)



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