Due to increased legal and market demands, the weight of a conventional car body will most likely increase in the future. At the same time, environmental demands will become stronger and weight reduction will play an important part in fulfilling them. These demands are contradicting and there are mainly two things that can solve it: The use of new materials and further optimization of the structure.High strength steel is the easiest way to implement improved materials in an integrated body structure. Press hardened steel is one of the most promising manufacturing techniques and in this project a B-pillar reinforcement was developed as an example.For linear analyses, structural optimization methods have been used for quite a while, but for crash simulations, trial and error has been the only alternative. One part of the project was to evaluate how the response surface method could be applied to car crash simulations.The results of the project were very good. With the same properties as the original B-pillar, the subsystem weight was reduced with 25%. A cost increase of 20 SEK/kg is expected.