The design of todays state-of-the-art rockfall barriers is currently based on experience and time consuming experimentation. Advanced simulation models are now under development to reduce prototyping time and development costs and will also provide a better understanding of complex mechanical systems under impact. In order to develop the models, extensive field testing was carried out. The individual components of the barriers were dynamically tested on a specially designed field apparatus, High energy full-scale tests on instrumented multi-span systems were additionally performed. The newly developed finite element program simulating the barriers is based on an explicit time step algorithm combined with special-purpose elements with large deformations and nonlinear material behavior for the netand brake-rings. For the interaction of rock and elements it also considers contact and sliding effects as well as friction.