Mathematical and semi-mathematical optimization methods are presented, which improve the lightweight structure of crash-relevant components of mobility systems. This is about the fulfillment of all requirements from laws or consumer protection tests. The article is a compilation of relevant methods for optimization that can be used to support the development process of complex mechanical systems. To evaluate the designs, crash simulations based on the finite elements are used in all presented methods. Topology optimization is mainly shown. So it’s about the optimization of the location and arrangement of structural elements and material. Methods for the efficient determination of necessary sensitivities are also presented. The article is intended to show the variety of different options for improving passive safety. The quality and performance of the used finite element simulation models are considered, especially for the presented methods using model reduction procedures and automatic generated sub-models.