The empirical design approach depends only on the previous experiences and experiences and on the other hand the mechanistic pavement design approach is to calculate the graphs and tables during the design process.Mechanistic approach in pavement design takes a step forward. Mechanics theory is used to predict traffic load and environmental conditions. The use of vertical compressive stress was first suggested by Kerkhoven and Mormon (1953) for the top of the subgrade as a criterion for establishing failure to reduce permanent strain. Saal & Pell (1960) suggested the use of horizontal tensile strain at the bottom of the asphalt layer which will minimize fatigue cracking. These suggestions and publications, along with many others, have been part of research by institutions, states, and agencies to improve the ME approach to pavement design. . The most recent EM-based method was draft (NCHRO, 2004) of NCHRO 1-37A. this incorporated nationally calibrated models to predict distress induced by traffic load and the environment.