# Mechanical-Empirical Pavement Design Guide Applied to Portuguese Pavement Structures
## 1 Introduction
The ATPD design thicknesses were used in the MEPDG for each case to predict the pavement performance reliabilities at the end of the 20-year design life. It was found that, when using the MEPDG, only the cases with a strong subgrade material and a low level of traffic met the default limit value for total pavement rutting. On the other hand, all sections failed due to excessive IRI values. [PERSON] et al. [10] continued later with another study to investigate the quality of the recently developed Canadian climatic database and the effect of climatic factors on flexible pavement performance using the MEPDG procedure. It was found that total pavement rutting and IRI showed sensitivity to climate changes. [PERSON] et al. [11] used the installed weigh-in-motion (WIM) systems at six highway locations to characterize traffic loads in Alberta for the MEPDG design. Seasonal and regional trends in traffic characteristics of the six WIM sites were investigated and compared with the default values in the MEPDG for two years. Truck traffic classification (TTC) and axle load distribution factor (ALDF) for the WIM sites showed deviations from the MEPDG defaults. Seasonal variations were also evident in the distribution of different classes of trucks throughout the year. Differences were attributed to cold climate conditions and special truck traffic in Alberta due to local industries. It was also found that the performance of flexible pavements was sensitive to TTC and ALDF. [PERSON] et al. [12] studied the development of traffic characteristics to facilitate the implementation of the MEPDG procedure in Idaho. Classification and weight data were collected at 25 WIM sites, but only 12 sites were found to have complete and accurate data. Predicted distresses and IRI values for a typical pavement section and traffic data obtained at the investigated WIM sites (level 1) were compared to predicted distresses/IRI using statewide/national (level 3) default traffic inputs. This comparison revealed that site-specific axle load spectra (ALS), vehicle class distribution factors (VCDF), and monthly adjustment factors (MAF) had a significant impact on longitudinal cracking. Statewide ALS yielded high differences in alligator cracking predictions, while statewide MAF and VCDF yielded only moderate differences compared to site-specific ALS. Very low prediction differences occurred in rutting when statewide/national default ALS, MAF, and VCDF were used as opposed to site-specific data. Furthermore, the level of input of the investigated traffic parameters was found not to affect IRI. Finally, they concluded that the statewide/national number of axles per truck could be used instead of site-specific values without sacrificing the accuracy of the pavement performance predictions. [PERSON] et al. [13] presented a study on using the MEPDG design software to evaluate the performance of typical Louisiana flexible pavement structures and compared it to the existing pavement performance data available in the Louisiana Pavement Management System. The results of the comparison between the measured and predicted pavement distresses showed a strong dependency on the type of pavement structure considered in the study. In general, the MEPDG rutting models tended to overpredict the total rutting for Louisiana's flexible pavements, whereas both fatigue cracking and IRI models in the MEPDG seemed to be adequate for most of the selected projects. The literature comprises other studies related to the evaluation of the MEPDG application [14; 15; 16; 17; 18]. However, to the best of our knowledge, none of them addresses the application of the MEPDG procedure to a complete country's catalogue of pavement structures. This paper presents and discusses the results of the application of the MEPDG procedure to the flexible pavement structures presented in the Portuguese Manual of Pavement Structures for the national road network [19].