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Publication Number: FHWA-RD-01-143
Date: October 2003

Distress Data Consolidation Final Report

Chapter 6: Conclusions and Recommendations

Distress data have been collected for more than 10 years through the LTPP project. Sufficient data now are available to begin examining trends in pavement performance. Prior to any rigorous analysis of the LTPP data, however, there is a need to assess the quality of the data. Therefore, the primary objective of this effort was to produce a comprehensive consolidated distress data set to reconcile differences between data collected using different methodologies. Although as many as 15 distinct distresses are included in the DIM for each pavement type, the analysis reported herein focused on the most commonly occurring distresses shown in table 24.

Table 24. Most commonly occuring distresses for various pavement types.

Fatigue Checking Corner Breaks Longitudinal Crack
Longitudinal Cracking Longitudinal Cracking Transverse Cracking
Transverse Cracking Transverse Cracking Patch/Patch Deterioration
Patch/Patch Deterioration Patch/Patch Deterioration Punchouts
Block Cracking    


The following conclusions are noteworthy:

Table 25. Categorization of discrepant surveys.

Human Factor Seasonal Effects Data Collection Methodology Evaluation Strategies Unknown
17 percent 0 percent 6 percent 36 percent 41 percent
  • Distress
  • Summarization
  • Thermal effects on crack width
  • Visibility of distress due to surface moisture
  • Manual vs. automated
  • Color, contrast, and depth perception
  • Resolution (e.g. hairline cracking)
  • Nonlinear increase in distress
  • Insufficient quantities of distress
  • Undocumented M&R*


In view of the preceding conclusions, the authors offer the following recommendations:


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