Fatigue is one of the main distress mechanisms considered in asphalt pavement design. Research efforts have focused on developing reliable fatigue prediction models based on strain, stress, or both (i.e., stiffness). The strain based fatigue failure criteria have an intrinsic weakness that the strain itself includes not only deformation due to damage but also deformation related viscoelastic and plastic effects. The stress used in the calculation of the stiffness is difficult to determine when cracks are developed in the material because the material is no longer a continuum body. Thus, this...