Actual research results in the automotive field show that there is a big potential in increasing active and passive safety by implementing intelligent driver assisting systems. Realizing such safety related system functions requires an electronic system without mechanical or hydraulic backup to de-couple the human interface from the vehicle functions, e.g., steering and braking.Safety critical functions without mechanical backup enforce new requirements in system design. Any faulty behavior of a component within the system must not lead to a malfunction of the overall system. Consequently in the system design fault-tolerance mechanisms in real time must be introduced. Active replication of a functional node is a proper solution to guarantee this real time fault-tolerance. Redundancy management of the functional nodes can be implemented by fail-silent replicas, i.e. a node behaves correctly or does not produce any output at all. This guarantees that the non-faulty replica is not disturbed and the system still performs the correct functionality.Since the steering functionality is the most safety critical function in a vehicle, the implementation of a Steer-By-Wire prototype seems to be the best evaluation of this concepts within the automotive area. The partners of the Brite-EuRam project „Safety related fault tolerant systems in vehicles (X-By-Wire)” are DaimlerChrysler Research, Fiat Research Center, Ford Europe, Volvo, Bosch, Magneti Marelli, Mecel, University of Chalmers, and the Vienna University of Technology. They analyzed, specified and even implemented a prototype of such a Steer-By-Wire case study.