Head impact safety is a significant consideration particularly in the design of passenger vehicles. Requirements for head impact protection against the upper interior of a vehicle as well as areas such as instrument panel are covered by the FMVSS 201 regulation in USA. In Europe, safety rules are anticipated for enhancing the head impact safety of pedestrians against the hood (i.e. bonnet) of a vehicle. The recommended test procedures for head impact safety demonstration generally involve the usage of freemotion Hybrid III and spherical headforms. In order to carry out the design of automotive head impact protection countermeasures in an efficient and cost-effective manner, simulation models need to be employed. The present paper deals with a new nonlinear lumped parameter model that can serve as a preliminary design tool. A new aspect of the current model is its ability to account for headform rotation during impact on vehicle targets. The present model is also suitable for parametric studies, and quantitatively assessing the effect of rotational motion of headform on head injury criterion (HIC). Based on results from the current lumped parameter model, it can be said that adherence to FMVSS 201 regulation may also ensure safe levels of rotational acceleration as related to head injury.