In this document it proposes two methods for the design of flexible pavements through the aashto and rational methods applied in the national road of the municipality of armero guayabal (Tolima), the description and subsequent comparison of each element is explained, as well as gradually developed the design of the flexible pavement. In the same way as the elements required for each method and the description of the relevant computer programs in each case. After making the calculations with the aashto and rational pavement design methods, a comparison of results is made.