The interest of the highway engineer and researchers are focused on road roughness and vehicle vibrations in the frequency range of interest, which corresponds to a wave number range appropriate for the prevailing traffic speed. Road profile is an important step for studying vehicle ride comfort. The aim of this work is to investigate the effect of road roughness on the ride comfort and rolling resistance for passenger cars. Mathematical models of a half vehicle for passive and semi-active suspension systems are developed to evaluate vehicle ride comfort in terms of suspension performance criteria. The ride performance, power consumed in rolling resistance and power dissipation in suspension for passive and semi-active suspension systems are finally evaluated