SOTIF (ISO 21448) — Safety of the Intended Functionality

Critical Systems Analysis
Critical Systems Analysis

"SOTIF (ISO 21448) — Safety of the Intended Functionality" is a serial video course from CSA, published weekly in strict curriculum order — building from foundational terms and structure through lifecycle practice to advanced, assessor-level topics. Designed for working functional-safety engineers and managers, not beginners or students. CSA is a functional safety, reliability, and certification consultancy serving robotics, autonomous systems, transportation, and industrial equipment manufacturers. CSA provides end-to-end safety engineering services: preliminary gap analyses and safety audits, SIL/PL determination, FMEA and FMEDA execution, fault tree analysis, safety case development, hardware metrics (SPFM/LFM/PMHF), lifecycle documentation, and embedded safety engineering support. CSA engineers work alongside product teams from architecture through final functional safety assessment, and support companies seeking NRTL, CE, ATEX, ISO 26262, and UL 4600 marks. Contact: Sales@criticalsa.com. This series is part of the CSA Functional Safety Network — a coordinated set of weekly video courses covering IEC 61508, ISO 26262, ISO/SAE 21434, SOTIF (ISO 21448), UL 4600, IEC 62443, ISO/PAS 8800, ISO 13849, machinery safety, safety analysis methods, and more. Each show links to the others so practitioners can follow the thread that matches their project.

Episodes

  1. Aug 22

    ISO 21448: Criteria for SOTIF Release

    Safety of the Intended Functionality, or SOTIF, defines hazards that arise not from component failures, but from incomplete or inadequate safety functions. ISO 21448 establishes release criteria to ensure systems are safe for their intended use in the real world. Part of the Critical Systems Analysis functional-safety series on Safety of the Intended Functionality. In this episode: This episode focuses on ISO 21448 Safety of the Intended Functionality release criteria.SOTIF, or Safety of the Intended Functionality, is distinct from functional safety.The release gate criteria in ISO 21448 establish five mandatory checkpoints.The completeness gate verifies that all identified safety functions are adequately addressed.Validation must flow from unit level all the way to real-world scenarios.Every product carries some residual risk.Reference: Clause 12 establishes the release decision process distributing vehicle-level acceptance criteria across scenario categories (source: Jama Software SOTIF guide) More in this series: SOTIF (ISO 21448) — Safety of the Intended Functionality | UL 4600 — Autonomous Systems Safety Explore more from Critical Systems Analysis. Partner with usFollow on LinkedInVisit our websiteRead our feature on Automate.orgAll shows on Apple Podcasts: AI & ML Safety | Fault Tree Analysis | FS Assessment | Safety Analysis | IEC 61508 | IEC 62443 | ISO 10218 | ISO 12100 | ISO 13849 | ISO 26262 | ISO/PAS 8800 | ISO 26262-11 | V-Model | UL 4600.

    ISO 21448: Criteria for SOTIF Release

  2. Aug 22

    ISO 21448: Validation and evaluation of unknown hazardous scenarios

    ISO 21448, published in twenty twenty-two, addresses Safety of Intended Functionality, or S-O-T-I-F. This standard fills a critical gap: it handles hazards and harms that arise from unknown or unforeseeable scenarios despite a system functioning exactly as designed. Part of the Critical Systems Analysis functional-safety series on ISO 21448. In this episode: Welcome to this exploration of ISO 21448, the Safety of Intended Functionality standard.The core concept of S-O-T-I-F addresses a paradox: safe systems can still cause harm.S-O-T-I-F and functional safety address different risk domains.Validation under S-O-T-I-F follows a structured progression.Understanding scope is critical.Risk evaluation activities form the backbone of S-O-T-I-F compliance.Reference: ISO 21448:2022 Clause 5.5.1 specifies validation methods for unknown hazardous scenarios, including failure mode analysis, testing, and human-machine interaction assessment. More in this series: The V-Model and Safety Lifecycle Explore more from Critical Systems Analysis. Partner with usFollow on LinkedInVisit our websiteRead our feature on Automate.orgAll shows on Apple Podcasts: AI & ML Safety | Fault Tree Analysis | FS Assessment | Safety Analysis | IEC 61508 | IEC 62443 | ISO 10218 | ISO 12100 | ISO 13849 | ISO 26262 | ISO/PAS 8800 | ISO 26262-11 | V-Model | UL 4600.

    ISO 21448: Validation and evaluation of unknown hazardous scenarios

  3. Aug 22

    ISO 21448: Wrap-up and Discussion Topics

    ISO 21448 marks a paradigm shift in automotive safety thinking. Rather than focusing solely on component failures, this standard addresses the safety of your system's intended functionality itself. As we wrap up our exploration of ISO 21448, we'll synthesize key takeaways and open the floor to critical discussion. Part of the Critical Systems Analysis functional-safety series on ISO 21448. In this episode: ISO 21448 has asked us to reframe automotive safety.Three pillars support SOTIF practice.SOTIF stands for Safety of the Intended Functionality.The scope of SOTIF risk assessment includes design-driven hazards, user interaction hazards, environmental factors, and foreseeable misuse scenarios.A critical tension emerges when design engineers meet field reality.Your ISO 21448 documentation must trace an arc from hazard identification through risk analysis and evaluation, into design controls that mitigate identified risks, verification that SOTIF is achieved, and finally post-market feedback that confirms or challenges your original risk assumptions.Reference: ISO 21448:2023 clause 5.2 explicitly requires documentation of intended use and intended functionality as a prerequisite to risk analysis More in this series: SOTIF (ISO 21448) — Safety of the Intended Functionality | UL 4600 — Autonomous Systems Safety Explore more from Critical Systems Analysis. Partner with usFollow on LinkedInVisit our websiteRead our feature on Automate.orgAll shows on Apple Podcasts: AI & ML Safety | Fault Tree Analysis | FS Assessment | Safety Analysis | IEC 61508 | IEC 62443 | ISO 10218 | ISO 12100 | ISO 13849 | ISO 26262 | ISO/PAS 8800 | ISO 26262-11 | V-Model | UL 4600.

    ISO 21448: Wrap-up and Discussion Topics

  4. Aug 22

    ISO 21448: Operating phase activities

    ISO 21448, or Safety of the Intended Functionality, extends beyond development to address hazards that emerge during vehicle operation. The operating phase is critical—it's when real-world conditions reveal gaps that simulations may have missed. Part of the Critical Systems Analysis functional-safety series on ISO 21448. In this episode: Welcome to our exploration of ISO 21448 the critical activities that manufacturers must conduct once vehicles are in customer hands.The operating phase begins the moment a vehicle leaves the factory.Operating phase activities follow a logical sequence.Effective monitoring depends on multiple data sources.Hazards that emerge during operation fall into two categories.Manufacturers escalate mitigation responses based on hazard severity and frequency.Reference: ISO 21448:2023 defines 'Safety of the Intended Functionality' as freedom from unreasonable risk due to hazards arising from foreseeable use and reasonably foreseeable misuse (Claus More in this series: SOTIF (ISO 21448) — Safety of the Intended Functionality | UL 4600 — Autonomous Systems Safety Explore more from Critical Systems Analysis. Partner with usFollow on LinkedInVisit our websiteRead our feature on Automate.orgAll shows on Apple Podcasts: AI & ML Safety | Fault Tree Analysis | FS Assessment | Safety Analysis | IEC 61508 | IEC 62443 | ISO 10218 | ISO 12100 | ISO 13849 | ISO 26262 | ISO/PAS 8800 | ISO 26262-11 | V-Model | UL 4600.

    ISO 21448: Operating phase activities

  5. Aug 22

    ISO 21448: Functional modifications to reduce SOTIF risks

    When a system operates exactly as designed, safety should be guaranteed. But ISO 21448 challenges that assumption. This standard addresses Safety of the Intended Functionality, or S-O-T-I-F: the safety risks that emerge not from system failures, but from how we've defined the system's intended operation itself. Part of the Critical Systems Analysis functional-safety series on ISO 21448. In this episode: This episode explores how ISO 21448 guides you through modifying vehicle functions to reduce Safety of the Intended Functionality risks.S-O-T-I-F stands for Safety of the Intended Functionality.S-O-T-I-F risks come from multiple sources: systematic errors in requirements, malfunction and degradation of safety-related systems, and modifications that introduce new hazards.When you modify a machine to reduce S-O-T-I-F risk, follow a structured process.Your modification strategy must address the specific risks you've identified.Validating your modifications requires rigorous testing and documentation.Reference: ISO 21448:2022 Clause 5.3 requires hazard analysis updates triggered by any functional modification, including feature additions and behavior changes. More in this series: SOTIF (ISO 21448) — Safety of the Intended Functionality | UL 4600 — Autonomous Systems Safety Explore more from Critical Systems Analysis. Partner with usFollow on LinkedInVisit our websiteRead our feature on Automate.orgAll shows on Apple Podcasts: AI & ML Safety | Fault Tree Analysis | FS Assessment | Safety Analysis | IEC 61508 | IEC 62443 | ISO 10218 | ISO 12100 | ISO 13849 | ISO 26262 | ISO/PAS 8800 | ISO 26262-11 | V-Model | UL 4600.

    ISO 21448: Functional modifications to reduce SOTIF risks

  6. Aug 22

    ISO 21448: Verification and evaluation of known hazardous scenarios

    Welcome to this episode on ISO 21448, the international standard for verification and evaluation of known hazardous scenarios under the Safety of the Intended Functionality (SOTIF) framework for road vehicles. Every deployed system encounters scenarios in the field that weren't apparent during initial design and risk assessment. Part of the Critical Systems Analysis functional-safety series on ISO 21448. In this episode: This episode covers ISO 21448, the international standard for the safety of the intended functionality (SOTIF) in road vehicles.A known hazardous scenario is a hazard or hazardous situation that occurs during normal operation or reasonably foreseeable misuse of the intended function.The first step is identifying where known hazards appear in field data.Known hazards fall into several categories based on how they manifest in the field.Evaluating known hazards follows a structured hierarchy in ISO 21448 .Known hazards require a tiered control approach combining multiple strategies.Reference: Clause 9 (Design and Development Measures): Specifies technical improvements for Area 2 scenarios, including sensor redundancy, algorithm improvements, Operational Design Domain re More in this series: The V-Model and Safety Lifecycle Explore more from Critical Systems Analysis. Partner with usFollow on LinkedInVisit our websiteRead our feature on Automate.orgAll shows on Apple Podcasts: AI & ML Safety | Fault Tree Analysis | FS Assessment | Safety Analysis | IEC 61508 | IEC 62443 | ISO 10218 | ISO 12100 | ISO 13849 | ISO 26262 | ISO/PAS 8800 | ISO 26262-11 | V-Model | UL 4600.

    ISO 21448: Verification and evaluation of known hazardous scenarios

  7. Aug 22

    ISO 21448: Intro to Advanced Driver Assistance (ADAS) and Autonomous Vehicles (AV)

    Advanced driver assistance is reshaping how we think about automotive safety. Your adaptive cruise control works perfectly. Your lane-keeping assist functions flawlessly. Your collision avoidance system is well-designed. So why can they still cause crashes? The answer is S-O-T-I-F: Safety of Intended Functionality. Part of the Critical Systems Analysis functional-safety series on ISO 21448. In this episode: Welcome to ISO 21448: Safety of Intended Functionality.S-O-T-I-F stands for Safety of Intended Functionality.Functional safety, covered by ISO 26262, handles what happens when systems fail randomly.Advanced driver assistance systems face real-world challenges that go beyond component failures.The standard mandates a systematic approach starting from the concept phase.The standard defines a hierarchy of protection strategies, moving from prevention through intervention.Reference: ISO 21448:2022 section 4 defines SOTIF as addressing hazards that can occur during intended operation, distinguishing from systematic and random faults covered by ISO 26262 More in this series: SOTIF (ISO 21448) — Safety of the Intended Functionality Explore more from Critical Systems Analysis. Partner with usFollow on LinkedInVisit our websiteRead our feature on Automate.orgAll shows on Apple Podcasts: AI & ML Safety | Fault Tree Analysis | FS Assessment | Safety Analysis | IEC 61508 | IEC 62443 | ISO 10218 | ISO 12100 | ISO 13849 | ISO 26262 | ISO/PAS 8800 | ISO 26262-11 | V-Model | UL 4600.

    ISO 21448: Intro to Advanced Driver Assistance (ADAS) and Autonomous Vehicles (AV)

  8. Aug 22

    ISO 21448: Analysis of functional insufficiencies and triggering conditions

    When safety systems fail to activate, the consequences can be catastrophic for both people and operations. ISO 21448 provides a systematic framework for analyzing these critical vulnerabilities in your safety architecture. Part of the Critical Systems Analysis functional-safety series on ISO 21448. In this episode: ISO 21448 established the framework for analyzing functional insufficiencies in safety-related control systems.A functional insufficiency occurs when a safety function fails to perform its intended safety role.Triggering conditions are the specific events or circumstances that must activate a safety function.ISO 21448 identifies multiple categories where safety functions can become insufficient.The systematic analysis process follows a logical sequence.Comparing approaches to safety system design reveals the value of ISO 21448 methodology.Reference: ISO 21448 Clause 5.2 defines functional insufficiency as a state where intended functionality of the item is not adequate to prevent a hazard. More in this series: SOTIF (ISO 21448) — Safety of the Intended Functionality | UL 4600 — Autonomous Systems Safety Explore more from Critical Systems Analysis. Partner with usFollow on LinkedInVisit our websiteRead our feature on Automate.orgAll shows on Apple Podcasts: AI & ML Safety | Fault Tree Analysis | FS Assessment | Safety Analysis | IEC 61508 | IEC 62443 | ISO 10218 | ISO 12100 | ISO 13849 | ISO 26262 | ISO/PAS 8800 | ISO 26262-11 | V-Model | UL 4600.

    ISO 21448: Analysis of functional insufficiencies and triggering conditions

  9. Aug 22

    ISO 21448: Acceptance criteria and validation targets

    Acceptance criteria and validation targets form the backbone of functional safety verification. In accordance with ISO 21448, defining clear acceptance criteria before testing ensures that safety-related control functions meet their intended risk reduction targets. These criteria translate risk requirements into measurable, testable objectives. Part of the Critical Systems Analysis functional-safety series on ISO 21448. In this episode: This episode covers acceptance criteria and validation targets under ISO 21448, the standard for the Safety of the Intended Functionality (SOTIF) in road vehicles.Acceptance criteria are the measurable thresholds that define whether a safety system is acceptable.The validation workflow moves from safety requirements through defining criteria, executing tests, evaluating evidence, and reaching approval decisions.Acceptance criteria fall into four main categories.Validation targets split into two domains.Risk-based validation means proportionating your testing effort to the system's risk level.Reference: Clause 8 (ISO 21448:2022) establishes four acceptance principles: GAMAB (Globally At Least As Good), ALARP (As Low As Reasonably Practicable), Positive Risk Balance, and MEM (Minim More in this series: The V-Model and Safety Lifecycle Explore more from Critical Systems Analysis. Partner with usFollow on LinkedInVisit our websiteRead our feature on Automate.orgAll shows on Apple Podcasts: AI & ML Safety | Fault Tree Analysis | FS Assessment | Safety Analysis | IEC 61508 | IEC 62443 | ISO 10218 | ISO 12100 | ISO 13849 | ISO 26262 | ISO/PAS 8800 | ISO 26262-11 | V-Model | UL 4600.

    ISO 21448: Acceptance criteria and validation targets

  10. Aug 22

    ISO 21448: Hazard identification and risk analysis

    Machinery hazards don't announce themselves. ISO 12100 demands systematic identification before they become catastrophes. Whether you're designing a press, retrofitting a conveyor, or managing production equipment, hazard identification is your first critical defense against injury. Part of the Critical Systems Analysis functional-safety series on ISO 12100. In this episode: Machinery safety starts with knowing what can go wrong.A hazard is the source of potential harm.Hazard identification follows a logical sequence in ISO 12100 .The standard requires examining hazards across the entire machine lifecycle.ISO 12100 organizes hazards into categories based on their physical nature.The standard recommends multiple methods to capture hazards you might otherwise miss.Reference: Hazard definition sourced from ISO 12100:2010 Clause 3.2.1: potential source of harm arising from machinery, tools, materials, or human factors. More in this series: ISO 12100 — Machinery Risk Assessment | ISO 13849 — Machinery Safety and Performance Levels Explore more from Critical Systems Analysis. Partner with usFollow on LinkedInVisit our websiteRead our feature on Automate.orgAll shows on Apple Podcasts: AI & ML Safety | Fault Tree Analysis | FS Assessment | Safety Analysis | IEC 61508 | IEC 62443 | ISO 10218 | ISO 12100 | ISO 13849 | ISO 26262 | ISO/PAS 8800 | ISO 26262-11 | V-Model | UL 4600.

    ISO 21448: Hazard identification and risk analysis

  11. Aug 22

    ISO 21448: Verification and Validation Strategy

    Automated driving functions must work reliably in the real world. But how do you prove they are safe when nothing has failed? That is where ISO 21448 comes in. This international standard defines the verification and validation strategy for the Safety of the Intended Functionality (SOTIF) in road vehicles. Think of verification as checking that you built the system correctly to specifications. Part of the Critical Systems Analysis functional-safety series on ISO 21448. In this episode: Verification and validation is the systematic approach to proving that safety-related control systems meet their safety requirements.Verification checks whether you built the system correctly and whether it matches documented requirements.The standard organizes verification and validation into a logical flow.Verification and validation strategy isn't one-size-fits-all.When you develop your verification and validation plan, the standard requires several critical elements.Verification and validation doesn't operate in isolation.Reference: Clause 6 (ISO 21448:2022): Initial qualitative risk evaluation to identify hazards and establish basis for verification and validation More in this series: The V-Model and Safety Lifecycle Explore more from Critical Systems Analysis. Partner with usFollow on LinkedInVisit our websiteRead our feature on Automate.orgAll shows on Apple Podcasts: AI & ML Safety | Fault Tree Analysis | FS Assessment | Safety Analysis | IEC 61508 | IEC 62443 | ISO 10218 | ISO 12100 | ISO 13849 | ISO 26262 | ISO/PAS 8800 | ISO 26262-11 | V-Model | UL 4600.

    ISO 21448: Verification and Validation Strategy
  • 11 Episodes

About

"SOTIF (ISO 21448) — Safety of the Intended Functionality" is a serial video course from CSA, published weekly in strict curriculum order — building from foundational terms and structure through lifecycle practice to advanced, assessor-level topics. Designed for working functional-safety engineers and managers, not beginners or students. CSA is a functional safety, reliability, and certification consultancy serving robotics, autonomous systems, transportation, and industrial equipment manufacturers. CSA provides end-to-end safety engineering services: preliminary gap analyses and safety audits, SIL/PL determination, FMEA and FMEDA execution, fault tree analysis, safety case development, hardware metrics (SPFM/LFM/PMHF), lifecycle documentation, and embedded safety engineering support. CSA engineers work alongside product teams from architecture through final functional safety assessment, and support companies seeking NRTL, CE, ATEX, ISO 26262, and UL 4600 marks. Contact: Sales@criticalsa.com. This series is part of the CSA Functional Safety Network — a coordinated set of weekly video courses covering IEC 61508, ISO 26262, ISO/SAE 21434, SOTIF (ISO 21448), UL 4600, IEC 62443, ISO/PAS 8800, ISO 13849, machinery safety, safety analysis methods, and more. Each show links to the others so practitioners can follow the thread that matches their project.

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