The analysis of the methodology for determining the coefficient of strength of pavement, based on the results of a visual assessment of the condition of pavement is performed. The traditional classification of the networks of cracks is considered, and the reasons for their arising on the Bolshie Uki - Znamenskoe road are analyzed. Traditional fatigue cracking and temperature tensile stresses are defined as main causes of cracks network. The feature of the emergence of networks of cracks on the pavement of the road Bolshie Uki - Znamenskoe, which consists in the appearance of these defects in sectors located on terrain with long standing groundwater, is revealed. Therefore, as a related cause of the appearance of a network of cracks, the effect of insufficient strength of a subgrade of cohesive soils and increased humidity was noted. Experimental work was carried out to determine the elastic deflections in the sectors with networks of cracks and the reference sector without defects. According to the experimental work, safety factors are determined, and mathematical models of the dependence of the coefficient of strength from the cell size of the cracks network are developed.