System architectures for safety critical automotive applications

As vehicle electronic control systems increase in both complexity and control authority there must be a commensurate increase in our ability to design and implement these systems safely. Sources of failure are described, and architectures for systems with and without a safe state are discussed. The use of common specifications, hardware and software are all seen as hazardous for very high integrity systems. Diversity is regarded as the best approach for providing the safety levels required and the preferred approach is to provide this by utilising checking and back-up systems which are designed against a different requirement, and have less functionality than the main control system. In this way the integrity of these systems can be kept high at a reasonable cost