In this paper the authors would like to present and share the measurements of load spectra and their modelling for pavement design purposes in the Mexican road network, which due to the intense level of trade with the United States present a very high percentage of heavy vehicles in the flow of vehicles and with high levels of load. Examples of these measurements are given in the country's main transport corridors. Damage spectra are also presented that are associated to each of the different axle types (i.e., single, dual, tandem, tridem or another one) by computing for instance the Miner damage coefficient in the same load ranges used in the definition of the load spectra. Is this frequency distribution of the Miner damage coefficient that is called damage spectra. The damage spectra seem to be a very useful tool to evaluate the pavement expected damage, i.e., rutting or fatigue cracking, induced for a given axle type. Moreover, it can be showed that there is a direct relationship between the forms in load and damage spectra. Some examples are presented to illustrate the damage spectra computations. The incorporation of these load spectra into mechanistic design methodologies and their implications in the definition of public policies for the preservation of the road network are discussed.