How do you design fail-operational systems for autonomous vehicle functions?

Fail-operational design ensures continued operation despite failures. Architecture approaches include: Redundant sensors with independent processing paths, dual computing platforms with arbitration, independent power supplies, redundant communication networks (diverse routing), and graceful degradation strategies. Design process involves: HARA identifying fail-operational requirements, fault tree analysis, common cause failure elimination, independence analysis between channels, safe state definition, transition timing analysis, and validation through fault injection. The system must detect failures, reconfigure to backup, and maintain minimum safe function. Key challenge is managing complexity while achieving required ASIL for autonomous driving.