Hazard Analysis & Risk Assessment (HARA)
Master the systematic process of identifying vehicle-level hazards, classifying risk parameters, and deriving safety goals with ASIL assignments, with a complete AEB worked example aligned to ISO 26262-3.
- Chapters
- 14
- Chapters
- Interactive Diagrams
- 10
- Interactive Diagrams
- Worked Example
- AEB
- Worked Example
- Synchronized
- Video
- Synchronized
Quick answers
- What is HARA in ISO 26262?
- Hazard Analysis and Risk Assessment (HARA) is the systematic process defined in ISO 26262-3, Clause 6, that identifies the vehicle-level hazards of an item and classifies their risk. For each hazardous event - a hazard occurring in a specific operational situation - three parameters are rated: severity (S0 to S3), exposure (E0 to E4) and controllability (C0 to C3). Their combination determines the ASIL, from QM through ASIL A to ASIL D. The output is a set of safety goals: top-level safety requirements, each carrying an ASIL, that drive the functional safety concept and everything downstream. HARA is performed on the item definition, before any design decisions.
- How is the ASIL determined from S, E and C?
- The three ratings feed a lookup defined in ISO 26262-3: for each hazardous event, the combination of severity, exposure and controllability yields QM, A, B, C or D. The logic is additive - the highest classifications on all three parameters (S3, E4, C3) produce ASIL D, and reducing any one parameter by one class steps the ASIL down one level. That is why justifications matter so much: an optimistic exposure or controllability rating quietly drops the ASIL and with it the required rigor for the whole development. The guide includes interactive ASIL tools and quizzes to make the determination mechanical rather than debatable.
A practical sample · no account needed
What is HARA in ISO 26262?
Hazard analysis and risk assessment identifies hazardous events caused by malfunctioning behavior of an item. It evaluates severity, exposure and controllability to determine the required automotive safety integrity level and formulate safety goals.
Unintended braking on a busy motorway and unintended braking while parking involve the same malfunction in different operational situations.
Would you assign an ASIL to the component alone?
Reveal the reasoning
No. Classify the hazardous event in its operational situation. Document the assumptions behind severity, exposure and controllability before deriving the safety goal. A component name or a failure mode alone is insufficient to justify an ASIL.
Illustrative learning example, not a project assessment. ISO 26262, Part 3 · About the academy
This example is public. A free account gives you access to the full videos for this topic; the written guide follows the plan access shown above.
Why it pays for itself
Run a complete HARA yourself
Work the full process from item definition through situation analysis, hazard identification and S/E/C classification to ASIL determination, with every step demonstrated on a complete AEB system analysis.
Classify S, E and C defensibly
Rate severity, exposure and controllability with written justifications an assessor will accept, supported by a searchable catalog of operational situations and hazardous events with reference classifications.
Write safety goals that hold up
Derive safety goals with correct ASIL assignment, fault tolerant time interval and safe state definition - the top-level safety requirements every downstream concept and analysis will trace back to.
What you’ll be able to do
Identify Vehicle-Level Hazards
Systematically discover hazards using FMEA, FTA, STPA, and HAZOP techniques with proper operational situation analysis.
Classify S, E, and C Parameters
Accurately rate Severity (S0-S3), Exposure (E0-E4), and Controllability (C0-C3) with data-driven justification.
Determine ASIL
Apply the ISO 26262 Table 4 matrix to derive ASIL ratings from QM through ASIL D for each hazardous event.
Formulate Safety Goals
Write verifiable, technology-independent safety goals with proper ASIL attribution, safe states, and FTTI specification.
Analyze ADAS & Autonomous Systems
Apply specialized HARA techniques for sensor-dependent systems including ML/AI considerations and SOTIF boundary routing.
Validate HARA Completeness
Verify coverage, correctness, and traceability using ISO 26262-3 Clause 6.4.6.1 verification aims and KPI metrics.
Chapter by chapter
- 01
Overview & Foundation
Understand why HARA is the cornerstone of functional safety, its objectives, when it is performed, and who participates in this cross-functional team exercise per ISO 26262-3 Clause 6.
- Safety Lifecycle Strip
- Concept Map
- SOTIF routing
- 02
HARA Fundamentals & Scope
Master precise ISO 26262 definitions of Malfunction, Hazard, Hazardous Event, Safety Goal, and ASIL. Explore the ASIL determination formula and classification parameters.
- ISO terminology
- ASIL formula
- Parameter scales
- 03
Methodology & Process
Follow the systematic 9-step HARA process from preparation through analysis to documentation, with input/output mapping and iteration guidance.
- 9-step process flow
- Good vs. bad examples
- Iteration guidance
- 04
ASIL Determination Matrix
Use the interactive ASIL calculator and filterable ISO 26262 Table 4 matrix. Deep-dive into Severity, Exposure, and Controllability with classification tables and real-world scenarios.
- ASIL Calculator
- Interactive matrix
- S/E/C deep dives
- 05
Safety Goal Definition
Learn to formulate proper safety goals with the standard pattern, see examples by system type (EPS, EBS, ACC), and understand combination and decomposition principles.
- Formulation patterns
- System examples
- Traceability flow
- 06
Hazard Identification Techniques
Compare and select from FMEA, FTA, STPA, and HAZOP for systematic hazard discovery. Includes the interactive technique selector and HAZOP guide words.
- Technique selector
- HAZOP guide words
- Selection guide
- 07
Advanced Exposure Analysis
Explore data-driven exposure assessment with mathematical models, ISO 26262 special rules for E0, fleet monitoring, naturalistic driving studies, and Monte Carlo simulation.
- Mathematical models
- Data collection methods
- Statistical evidence
- 08
FTTI & Safe States
Understand the Fault Tolerant Time Interval from fault occurrence to safe state. See the animated FTTI timeline, deduction methodology, and ASIL-based timing guidelines.
- FTTI Timeline
- Timing budgets
- ASIL guidelines
- 09
ADAS-Specific Analysis
Specialized hazard analysis for ACC, AEB, LKA, BSD, and TSR systems with bow-tie diagrams, ML/AI considerations, and SOTIF boundary routing.
- Bow-tie diagrams
- ML/AI considerations
- SOTIF routing
- 10
Trucks, Buses & Trailers
Apply HARA to heavy commercial vehicles per ISO 26262-3 Clause 6.4.5. Compare ASIL assignments across vehicle types and explore articulated vehicle hazards like jackknife.
- Vehicle type comparison
- Jackknife diagram
- Annex B categories
- 11
Distributed Functions
Handle vehicle-level functions spanning multiple E/E items. Learn ASIL inheritance, safety goal referencing, and how architecture determines ASIL flow.
- ASIL inheritance
- Architecture impact
- Cross-item tracing
- 12
Validation & Evidence
Demonstrate HARA completeness with verification aims per Clause 6.4.6.1, KPIs, traceability visualization, and assessment-ready documentation packages.
- Traceability visual
- KPI metrics
- Evidence requirements
- 13
AEB Worked Example
Walk through a complete end-to-end HARA for an Automatic Emergency Braking system: item definition, architecture, operational situations, S/E/C assessment, and safety goals.
- Architecture diagram
- Full S/E/C assessment
- Safety goals & FTTI
- 14
Advanced Industrial Topics
Explore Level 3 automated driving HARA, Delta-V severity thresholds, EPS FTTI case study, monitoring and limiting functions, energy-based HARA, and EV charging analysis.
- L3 automation
- EPS case study
- EV charging HARA
Not just text: the visual toolkit
Interactive ASIL Calculator
Select Severity, Exposure, and Controllability from dropdowns and instantly see the resulting ASIL with color-coded classification and requirements summary.
ASIL Determination Matrix
Full ISO 26262 Table 4 with click-to-filter by ASIL, hover highlighting, and a live requirements panel showing metrics and verification targets.
Safety Lifecycle Strip
Visual diagram showing exactly where HARA sits within the ISO 26262 concept phase and how it feeds into subsequent safety development activities.
Concept Map
Animated relationship diagram mapping HARA inputs, process steps, and outputs with interactive connections between key concepts.
Bow-Tie Diagrams
Cause-event-consequence visualizations for each ADAS hazard, showing prevention barriers and mitigation strategies with safety goal linkage.
FTTI Timeline
Animated timeline showing fault detection, reaction, and safe state transition intervals with an AEB 300ms example.
Traceability Visualization
Six-column interactive grid tracing from Operational Situations through Hazards, Safety Goals, FSRs, TSRs to Test Cases with forward and backward trace modes.
AEB System Architecture
Detailed engineering-style SVG showing sensors, ECU software components, actuators, CAN bus connections, and system boundary for the worked example.
Hazard Technique Matrix
Interactive quadrant selector for comparing FMEA, FTA, STPA, and HAZOP techniques with pros, cons, and use-case guidance.
Jackknife Technical Illustration
SVG illustration of articulated vehicle dynamics showing normal operation vs. jackknife event with fifth-wheel coupling and danger zone visualization.
Automatic Emergency Braking (AEB) Worked Example
Every HARA concept is applied to a complete AEB system analysis, demonstrating the full process from item definition through ASIL determination to safety goal derivation.
- Item definition with functional behavior and ODD
- Preliminary architecture with sensor/ECU/actuator mapping
- 4 operational situations with exposure ratings
- Complete S/E/C assessment with justification
- ASIL determination: ASIL D, D, C, and A results
- 3 safety goals with FTTI and safe state definitions
Unlock full AEB analysis in course
Who this guide is for
- Engineers running or contributing to their first HARA workshop
- System engineers who inherited an ASIL and want to understand where it came from
- Teams standardizing their operational situation catalogs and S/E/C rating justifications
- Anyone preparing for certification exams or interviews where ASIL determination is tested
Frequently Asked Questions
Common questions about Hazard Analysis & Risk Assessment (HARA)
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