The ever increasing deterioration of the roadways in this country, especially in winter, was observed in the last years. The main reason is in the systems of roadway structures that are unadequate according to the increasing traffic. The author treats in detail the large researches carried out on the pilot roadways in America in the years 1958—1960 that were given the name AASHO Test. The results of the mentioned Test are applied to the roadway conditions in this country, the roadway durability being evaluated according to:

— influence of various vehicles on the roadway durability,

— influence of single roadway layers on the road durability,

— durability of roadway at compound traffic.

The results, that the author has come to in his

analytic study, give the directives regarding the systems of roadway construction and dimensioning, as well as the subgrade and surface materials for construction of single roadway layers.