Innovation cycles in automotive industry have become shorter and shorter during the last ten years accompanied by increased complexity of systems. For this reason simulation has become a standard method within the process of product development. To reduce costs and time, an easy model exchange between manufactures and suppliers based on a standardized modeling language is necessary. VHDL-AMS is a standardized hardware description language to model and simulate digital, analog, and mixed-signal systems consisting of electrical and nonelectrical parts. Major German car manufacturers and suppliers are checking the suitability of the language for real world heterogeneous automotive systems. The VDA/FAT Working Group AK 30 "Simulation of Mixed Systems with VHDL-AMS" is organized within the Association for Research in Automobile Technology (FAT - Forschungsvereinigung Automobiltechnik) of the German Association of the Automotive Industry (VDA - Verband der Automobilindustrie). It promotes the relationship between car manufactures and their suppliers concerning simulation of mixed systems and model exchange. Further information about model libraries VHDL-AMS = Very High Speed Integrated Circuit Hardware Description Language - Analog and Mixed Signal