This paper presents a new conceptual model, the XBWModel. Distributed computing is becoming a cost effective way to implement safety critical control systems. To support the development of such systems the XBW conceptual model was developed. The model describes the time behavior and distribution properties of a system in such a way that static scheduling and systematic fault tolerance can be applied. The conceptual model also enables the definition of an appropriate fault model. This fault model along with the XBW-model allow efficient and systematic use of well known software based error detection methods. A distributed steer-by-wire control system is described, which is developed according to the model. The XBWModel is developed within in the European Brite-EuRam III project X-By-Wire.