In an effort to improve pavement design for North Carolina roads, NCDOT has adopted the AASHTOWare Pavement ME Design software. A critical component of the software is the Enhanced Integrated Climatic Model (EICM), which accounts for environmental effects. The EICM requires hourly historical climate records for the entire expected lifespan of the road, yet NCDOT presently has access only to small 5-year samples of climatological data from select locations. These short records must be repeated to fill in data for long analysis periods. Studies have shown that repeating small samples of climatic data may adversely affect pavement performance predictions.
This report describes the development of long-term, high-quality, historical climate data (HCD) files for use by the EICM at multiple locations across North Carolina. Ordinary kriging and other spatial and short-term temporal interpolation techniques address the significant gaps in data coverage present in the observational record so that the new HCD files consist of continuous hourly data that span a period of 35 years. Sensitivity tests assess the impact of the improved HCD files on pavement performance predictions and reveal statistically significant differences in concrete pavement performance measures between Pavement ME Design simulations with and without the new HCD files.
The new climate data more subtly influence pavement performance predictions for flexible pavement designs. Nevertheless, the poor quality of the original climate data samples warrants a recommendation that NCDOT use the improved climate files in the development of future pavement designs to boost confidence in pavement performance predictions.
