Functional Safety – New Vehicle Development: Common Pitfalls
Functional Safety in New Vehicle Development: Common Pitfalls
Introduction: Why Functional Safety Still Fails
As vehicles become increasingly software-defined and reliant on electronic control units (ECUs), achieving functional safety is more challenging than ever. First, we identify recurring pitfalls across the safety lifecycle—from hazard analysis to production—and then present strategic mitigation practices for each. Ultimately, this guide empowers teams to build ISO 26262-compliant systems that are reliable, auditable, and safe by design.
Despite widespread ISO 26262 adoption, functional safety shortcomings continue to trigger costly recalls, unplanned downtime, and regulatory scrutiny. Moreover, these failures often stem from misapplied or inconsistently executed safety practices rather than gaps in the standard itself. By proactively identifying and addressing these recurring challenges, development teams can reduce project risk and deliver more resilient systems.
1. Weak or Incomplete Hazard Analysis and Risk Assessment (HARA)
Problem: Teams sometimes rely on template-based HARA documents that fail to capture vehicle-specific hazards and operational edge cases.
Impact: Consequently, underestimating safety goals or misclassifying ASIL levels can compromise the entire safety concept.
Mitigation: Conduct scenario-based HARA workshops involving cross-functional experts (systems engineering, validation, cybersecurity) to capture all realistic failure modes and operating scenarios.
2. Overreliance on Safety Mechanisms Without Justification
Problem: Some design teams include complex hardware or software mechanisms without solid safety-case evidence, hoping to “check the box” for ASIL compliance.
Impact: This approach adds cost and complexity without enhancing safety integrity.
Mitigation: Use FMEDA and diagnostic coverage analysis to justify every mechanism’s effectiveness, clearly mapping coverage back to required ASIL objectives.
3. Late Engagement of Safety in System Architecture
Problem: Safety engineers are often brought in after architecture decisions are finalized, limiting their influence on partitioning and interface control.
Impact: As a result, convoluted safety paths and increased failure propagation risk emerge.
Mitigation: Integrate functional safety activities into early architecture definition and platform decisions, aligning safety elements with system interfaces from the start.
4. Inadequate Tool Qualification and Traceability
Problem: Safety-critical software is frequently built using toolchains and simulators that lack ISO 26262 qualification.
Impact: This creates gaps in tool confidence levels (TCL) and breaks traceability from requirements through test evidence.
Mitigation: Document tool confidence strategies, qualify critical tools where necessary, and maintain requirements traceability with ALM systems like DOORS or Jama.
5. Failure to Capture Safety Requirements in Supplier Contracts
Problem: Safety requirements may not be explicitly communicated or contractualized with Tier 1/Tier 2 suppliers.
Impact: This leads to incomplete DFMEAs, misaligned safety cases, and integration delays.
Mitigation: Include safety goals, ASIL decompositions, and validation responsibilities in supplier SoWs. Require safety plans and evidence submissions at program gates.
6. Inconsistent Safety Case Construction
Problem: Safety cases are often built in silos without centralized ownership or clear structure.
Impact: Certification efforts stall due to inconsistent evidence, redundant documentation, or ambiguous rationale.
Mitigation: Appoint a dedicated safety-case lead and use modular, argument-based tools (e.g., Medini, GSN) to construct logical chains of evidence and assumptions.
7. Weak Integration Between Safety and Cybersecurity
Problem: Functional safety and cybersecurity teams frequently operate in parallel, using different risk vocabularies and processes.
Impact: This separation causes duplication of effort, conflicting mitigations, or blind spots in overall system safety.
Mitigation: Establish a unified TARA + HARA framework and coordinate safety and security validations, particularly for OTA updates and ADAS functions.
8. Overuse of Passive Safety Arguments for Active Systems
Problem: Developers sometimes apply passive safety assumptions (e.g., airbag timing windows) to active functions (e.g., lane-keeping).
Impact: Misaligned response-time expectations can result in unrealistic fault reaction strategies.
Mitigation: Model dynamic behaviors in simulated environments using CarMaker or PreScan, aligning system performance windows with driver interaction and environmental variables.
Conclusion: Why Functional Safety Still Fails
Avoiding these common functional safety pitfalls is not just about process compliance—it’s about achieving real-world robustness in systems that must operate flawlessly under complex, uncertain conditions. By proactively addressing these challenges and validating mitigation strategies, automotive teams can reduce rework, improve audit outcomes, and deliver vehicles that are safer by design.
Series Positioning & Next Steps
This article complements earlier installments: Article 1 (Foundations & Frameworks), Article 2 (Business Case), Article 3 (Lifecycle & Implementation), Article 4 (Challenges & Best Practices), and Article 5 (Validation & Verification Techniques). Next, we will explore advanced Lifecycle assurances and Post SOP Safety Monitoring in Article 7.
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Real-World Case Studies & Lessons Learned
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Regulatory Compliance & Supplier Roles
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Validation & Verification Techniques
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Functional Safety in EV/ADAS/SDV
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Emerging Trends: AI & Over-the-Air Updates
Series Index: Functional Safety in Automotive
- Foundations & Frameworks: An ISO 26262 Guide to Automotive Functional Safety: https://georgedallen.com/functional-safety-new-vehicle-development-compliance/
- ISO 26262 Design Process: From Safety Goals to Implementation: https://georgedallen.com/why-functional-safety-matters-new-vehicle-development/
- ASIL Decomposition and Redundancy Management: https://georgedallen.com/functional-safety-new-vehicle-development-iso-standards/
- Functional Safety Implementation in Vehicle Platforms: https://georgedallen.com/functional-safety-new-vehicle-development-vehicle-platforms/
- The Role of Functional Safety in ADAS and Autonomous Systems: https://georgedallen.com/functional-safety-new-vehicle-iso-26262-implementation/
- Why Functional Safety still fails ← You are here
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Designing for Lifecycle Assurance and Post-SOP Safety Monitoring
Other References:
- ISO, ISO 26262: Road Vehicles — Functional Safety, Parts 1–10, 2nd Edition, 2018.
SAE J2980: Considerations for ISO 26262 Hazard Analysis, SAE International, 2011.
ETAS, “Best Practices for Safety-Critical Development in Automotive.”
Jama Software, “Functional Safety & Requirements Management.”
VDA/SAE, Handbook on Functional Safety for ADAS and Autonomous Systems, 2021.
ISO/SAE 21434: Road Vehicles — Cybersecurity Engineering, 2021.
Embitel, “HARA by ISO 26262 Standard Infographic,” www.embitel.com/blog/embedded-blog/hara-by-iso-26262-standard-for-your-functional-safety-project
Jama Software, “Guide to Automotive Safety Integrity Levels (ASIL),” www.jamasoftware.com/requirements-management-guide/automotive-engineering/guide-to-automotive-safety-integrity-levels-asil/
Systems Engineering References:
- ISO standards: https://www.iso.org/standard/43464.html
- V-Model reference: https://georgedallen.com/systems-v-model-strategy-in-automotive-design/
- https://georgedallen.com/new-engineering-ethics-fundamentals-of-product-development/
- https://georgedallen.com/objectivist-philosophy-in-new-engineering-ethics/
About George D. Allen Consulting:
George D. Allen Consulting is a pioneering force in driving engineering excellence and innovation within the automotive industry. Led by George D. Allen, a seasoned engineering specialist with an illustrious background in occupant safety and systems development, the company is committed to revolutionizing engineering practices for businesses on the cusp of automotive technology. With a proven track record, tailored solutions, and an unwavering commitment to staying ahead of industry trends, George D. Allen Consulting partners with organizations to create a safer, smarter, and more innovative future. For more information, visit www.GeorgeDAllen.com.
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