The guarantee of traffic conditions with safety and comfort is one of the primary aims during a road structure design. Thus, this study aims to contribute to the roughness prediction, represented by the International Roughness Index (IRI), by developing models that describe the functional performance of Brazilian pavements. With monitoring actions carried out in sites located in Santa Maria/RS and Rio de Janeiro/RJ, the paper sought to evaluate the IRI's evolution. The mechanistic methodology was inserted to the study's scope by predicting the IRI evolution using the average fatigue damage, which was calculated with FlexPAVETM software. The procedure enabled the development of a mechanistic-empirical model, based on the initial IRI obtained after the end of the construction process and the computationally asphalt layers calculated damage. The developed model was also validated with other sites within the Brazilian territory, which results in significant practical applicability.