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Research and Development (R&D) Project Sites

Project Information
Project ID:   FHWA-PROJ-11-0110
Project Name:   Evaluation of Long-Term Pavement Performance Program Climatic Data for Use in Mechanistic-Empirical Pavement Design Guide Calibration and Other Pavement Analyses
Project Status:   Completed
Start Date:  May 18, 2011
End Date:  December 30, 2015
Contact Information
Last Name:  Wiser
First Name:  Larry J
Telephone:  202-493-3079
E-mail:  larry.wiser@dot.gov
Office:   Office of Infrastructure Research and Development
Team:   Long-Term Pavement Performance Team [HRDI-30]
Program:   Long-Term Pavement Performance
Project detail
Roadmap/Focus area(s):   Infrastructure Research and Technology Strategic Plan and Roadmap
Project Description:   The current Climate (CLM) module of the Long-Term Pavement Performance (LTPP) database began as the Environment (ENV) module in 1992, with major revisions and enhancements performed in 1998. Since 1998, pavement technology and the use of climatic data have evolved (with adoption of the Integrated Climatic Model in the Mechanistic-Empirical Pavement Design Guide (MEPDG), for example), and there is a need for a reassessment of climatic data in general, and the sufficiency of LTPP climatic data collection specifically. During the last climate data update performed by the LTPP program in 2008, a need has developed to create a time series-based operating weather stations (OWS) selection strategy. The reason for this is over the 20 years of the LTPP program, new weather stations have been added, others are no longer operational, and the locations of existing weather stations have changed, although their station identification remained the same. There is a need to develop a methodology to treat estimates of location-specific climate data from surrounding weather stations whose locations and characteristics change over time. There is also a need to develop an estimate of variability or uncertainty in climate estimates derived from the averaging process of nearby weather stations. The National Cooperative Highway Research Program (NCHRP) 1-34D study on pavement drainage found a better correlation between the Thornthwaite Moisture Index (TMI), which is a climate-soil moisture holding potential interaction parameter, than traditional precipitation-based climate indices. The LTPP Automated Weather Station monitoring measurements have been terminated; however, no assessment of the value of the solar radiation data collected by this study have ever been made against other data sources, nor has the use of solar radiation data from other data sources for more widespread inclusion in the LTPP program been assessed. It is not yet known how issues, if any, associated with “global warming” caused by increases in solar output, a decrease in the ability of the earth’s atmosphere to reflect this radiation, or a combination of these effects, will affect the service life of pavement materials being used today.
The key project objective is to develop guidance for implementing climatic data for use in Mechanistic-Empirical Pavement Design Guide (MEPDG) calibration and other pavement analyses.
Product Type:   Data
Draft standard, specifications, or guidelines
Research report
Test Methodology:   Identify anomalies that persist and advance the use of climate data in infrastructure engineering applications.
Other Information:   LTPP Analysis Plan | Objective 3 | Outcome A | Project 7 | Priority Critical | Sequence 2
Partners:   Federal Highway Administration: Office of Research, Development, and Technology - Office of Infrastructure Research and Development; Role(s): Advisory, Technical, Other stakeholder
Expected Benefits:   Climate data is a fundamental input to pavement engineering research and practical applications. A great deal of groundbreaking work has been performed by Long-Term Pavement Performance to characterize and summarize climatic data for test sections. Lessons learned and improvements to climatic data collection are needed to support other fundamental research for pavement design, pavement performance, and to evaluate climatic change effects on pavements. The payoff potential is large, as this study has broad applications to the science of pavement engineering and future pavement performance studies conducted by all highway agencies.
Deliverables: 1. Name: Final report.
Product Type(s): Research report, Data
Description: The deliverable is a final report documenting the research approach, key findings, lessons learned from the Long-Term Pavement Performance (LTPP) climatic program, recommendations, and implications.
Publication URL(s):
2. Name: TechBrief
Product Type(s): Techbrief
Description: This TechBrief describes evaluating the use of the Modern-Era Retrospective Analysis for Research and Applications (MERRA) product as an alternative climatic data source for the Mechanistic-Empirical Pavement Design Guide (MEPDG) and other transportation infrastructure applications.
Publication URL(s):
3. Name: Stand-alone guide.
Product Type(s): Research report, Draft standard, specifications, or guidelines
Description: A guide shall be written for use by pavement practitioners to determine climatic data elements necessary for a variety of common pavement engineering analyses, including sources for obtaining climatic data based on lessons learned from the Long-Term Pavement Performance (LTPP) program. The guide should provide recommendations regarding the collection, analysis, and reporting of climatic data elements including recommendations as to best practices to combine existing climate stations to determine a point specific climate for use in analysis.
FHWA Topics:   Roads and Bridges--Pavement and Materials
TRT Terms:   Pavement Performance
Climate Change
Data Collection
FHWA Disciplines:   Pavement and Materials
Subject Areas:   Design


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