This paper describes a parametric study of foam material properties for interior car surfaces using finite element calculations. Two different head models were used for the impact simulations, a Hybrid III dummy head and a biomechanical head model. The objective was to study the head injury criterion (dummy) (HIC(d)), the angular velocity, the resultant acceleration and, for the human head models, the strain in the brain tissue and the stress in the skull for a variation in foam material properties such as stiffness, plateau stress and energy absorption. The analysis gave at hand that the best choice of material properties with respect to impact using the Hybrid III head model reached different results compared to an impact with the biomechanical head model. For a purely perpendicular impact, the HIC(d) for the head model managed to predict the strain level in the brain quite well. Even though the HIC reached acceptable levels for both a perpendicular and oblique impact towards a 31 kg/m3 EPP padding, the maximum strain in the human head model for an oblique impact was almost twice suggested allowable levels. The difference in the strain in the brain between an oblique and perpendicular impact when impacted with same initial velocity towards the same padding was not predicted by the HIC(d).