Site-Specific Versus Pavement Mechanistic-Empirical Default Traffic Data on Interstate Pavement Performance

This study investigates the effects of different site specific traffic inputs on predicted pavement distresses in New Mexico. Two major interstate highways were considered in this study: Interstate-40 (I-40) and Interstate-25 (I-25). Site specific traffic inputs were developed using Weigh-in-Motion (WIM) data collected from the pavement sites. WIM data were analyzed using an advanced and updated software, which can take care of error data, if any. Then a comparative study was conducted using the AASHTOWare pavement Mechanistic-Empirical (ME) Design Software. Different input parameters such as site specific axle load spectra, vehicle class distribution, monthly adjustment factor, hourly distribution, etc. were studied. Results show that axle load spectra have a great influence on predicted pavement performance. Vehicle class distribution, directional distribution, lane distribution, and standard deviation of lateral wander have a moderate impact on pavement performance. Monthly adjustment factor, axle per vehicle, axle spacing and operational speed have very little effect on the predicted pavement performance. On the other hand, predicted pavement performance is insensitive to hourly distribution and wheelbase distribution.