Flexible pavement is composed from an asphalt concrete layer, granular base and subbase layers, and the natural subgrade. The granular material that forming the granular layers are subjected to static and dynamic load. In this book a computer program SDSL-CAD (Simulation Different Shape of Load by using Computer Aided Design) is developed to study the effect of different shape of traffic load by using equivalent radius of tire imprint on stresses, strain, and deflection results, at different value of modulus of elasticity of granular layer. The multilayer elastic theory is used in SDSL-CAD program to analyze the traffic load under different types of axles and tires configuration and material properties of pavement layers.