ISO 26262 is the automotive adaptation of IEC 61508 for functional safety of electrical and/or electronic (E/E) systems installed in series-production road vehicles. First published in 2011 and revised in 2018, the second edition extends the scope from passenger cars to all road vehicles (except mopeds). It provides a risk-based safety framework and lifecycle spanning concept, development, production, operation, service, and decommissioning.

Key ideas

  • Safety lifecycle with defined work products from concept to decommissioning, including hazard analysis and risk assessment (HARA), safety goals, functional and technical safety concepts, safety requirements, verification/validation, and safety case with confirmation measures
  • Risk classification via Automotive Safety Integrity Levels (ASIL A–D; D highest) derived from severity (S), exposure (E), and controllability (C); below ASIL A is quality management (QM)
  • System, hardware, and software development with requirements for architecture (e.g., independence and freedom from interference), diagnostics and safety mechanisms, hardware metrics (e.g., single-point and latent fault metrics), and software design/verification
  • Supporting processes including configuration/change management, tool qualification, qualification of existing components, documentation management, and independent reviews, audits, and assessments

Structure (2018 edition)

  1. Vocabulary
  2. Management of functional safety
  3. Concept phase (incl. HARA and safety goals)
  4. Product development at the system level (functional/technical safety concepts, allocation)
  5. Product development at the hardware level (safety mechanisms, hardware metrics)
  6. Product development at the software level (requirements, design, implementation, verification)
  7. Production, operation, service, and decommissioning
  8. Supporting processes (configuration/change management, tool and component qualification, documentation)
  9. ASIL-oriented and safety analyses (e.g., FMEA/FMEDA, DFA, dependent failure analysis)
  10. Guidelines on ISO 26262 (interpretation and guidance)
  11. Guidelines on application to semiconductors
  12. Adaptation for motorcycles

Quality Attributes Required or Emphasized

The standard centers on functional safety and systematically addresses attributes that help achieve and demonstrate safety of E/E systems.

Attribute Relevance in ISO 26262
Auditability Confirmation measures (independent reviews, audits, assessments) and safety case evidence enable external evaluation.
Availability Indirectly managed: safety-related functions must be available as required for safety or move to a defined safe state; availability trade-offs are analyzed during HARA and design.
Compliance Conformance with normative requirements and documented tailoring to demonstrate adherence to the standard.
Configurability Variants and parameterization are controlled via configuration/change management to maintain safety across product lines.
Dependability Umbrella attribute (availability, reliability, maintainability, safety) supported by the safety lifecycle, analyses, and confirmation measures.
Fault Isolation Freedom from interference and partitioning prevent cascading effects between elements of different criticality.
Fault Tolerance Redundancy, diagnostics, and safety mechanisms ensure continued safe operation or controlled transition to a safe state.
Integrity Integrity of safety-related data and control flows avoids erroneous actuation and supports freedom from interference.
Maintainability Controlled change and configuration management preserve safety after modifications across the lifecycle.
Observability Diagnostic coverage and monitoring detect faults and support safe reactions.
Portability / Reusability Qualification and integration of existing SW/HW and pre-qualified components enable safe reuse across platforms.
Reliability Random hardware faults and failure modes are analyzed (FMEA/FMEDA) to support hardware metrics and safety targets.
Robustness Architectural and implementation measures handle faults and perturbations without loss of safety.
Safety Core objective: reduce unreasonable risk from hazards due to malfunctions using a defined safety lifecycle and ASIL-based risk reduction.
Security Coordinated with ISO/SAE 21434; security controls are considered where necessary to prevent threats from causing safety hazards.
Testability Extensive verification and validation across all lifecycle phases, including coverage-based testing and regression.
Traceability End-to-end traceability from safety goals through requirements, design, implementation, tests, and safety case.

References

Official Standards Documents

  • IEC 61508 — Functional safety of E/E/PE systems
  • ISO/PAS 21448 — Safety of the Intended Functionality (SOTIF)
  • ISO/SAE 21434 — Road vehicles — Cybersecurity engineering
  • SAE J2980 — Considerations for ISO 26262 ASIL hazard classification
  • Automotive SPICE (ASPICE)

Additional Resources