In recent years, a considerable effort has been made to develop a new generation of asphaltic materials based on a combination of polymers and asphalts. Regular and polymer-modified asphalts are studied via fractional relaxation processes, represented here by a fractional rational form of the complex modulus, G*. Basic properties of this complex modulus and the forms of generated constitutive equations are studied. Relaxation times of the model are related via a pseudospectrum to the phase angle lag.