Sensitivity of M-E PDG Level 2 and 3 Inputs Using Statistical Analysis Techniques for New England States

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Implementation of the Mechanistic-Empirical Pavement Design Guide (M-E PDG) by state highway design agencies necessitates transition from their currently followed pavement design practices along with additional data collection on the large number of inputs incorporated in the M-E PDG. This paper presents a data collection methodology that is representative of a real pavement section instead of a model pavement section or obtaining data from knowledge of engineering principles and experience. A procedure to design field studies is developed such that state highway design specifications can be adjusted if needed and transformed into M-E design guidelines to aid the implementation process. Statistical analysis of the predicted performance data is conducted to assess the sensitivity of Level 2 and 3 inputs on pavement distresses. A roadmap for documentation of design data is proposed based on case-studies from two states, New Hampshire and Connecticut. Input parameters considered to critically affect pavement distresses are identified from previous research results and literature review. Data sources for the corresponding M-E PDG inputs were identified and values for input parameters were selected based on variations that practically occur during pavement design, including tolerances on material properties. Analysis of variance was conducted on the predicted performance data. Percentage variation in the predicted distresses explained by each input variable was calculated and sensitivity levels were determined. Correlation ratio η^2 was used due to the deterministic nature of M-E PDG output. Independent data collection recommendations were made for both states on the basis of the study.