This paper describes progress in CAE techniques for the simulation of interior head impact (IHI) tests to FMVSS 201. Validation of the FT-Arup Free Motion Headform finite element model as a predictive tool for IHI is shown. Details of modelling the behaviour of plastic trim under impact conditions are included, and an efficient method of setting up the many load cases is described. Results are compared with test, showing the importance of the level of detail in the models. Finally, some models are presented that illustrate the effect of using the same Body-in-White for multiple tests at the same impact point, which is a common testing procedure.