Hands-On: Safety Plan Creation - Functional Safety (ISO 26262)

Exercise 1: Define Project Scope for an ADAS System

Example Item: Forward Collision Warning + Emergency Braking (FCAB)

  Item boundary:
  ┌───────────────────────────────────────────────────────────────────┐
  │  FCAB Item                                                         │
  │  ┌──────────────┐  ┌──────────────┐  ┌──────────────────────────┐ │
  │  │ Radar Sensor │  │ Camera ECU   │  │ FCAB Domain Controller   │ │
  │  │ (77 GHz)     │  │ (Front cam)  │  │ ├── Perception fusion    │ │
  │  └──────┬───────┘  └──────┬───────┘  │ ├── Threat assessment    │ │
  │         │                 │          │ ├── Driver warning (HMI) │ │
  │         └─────────────────┘          │ └── Brake actuation req. │ │
  │                                      └───────────┬──────────────┘ │
  └──────────────────────────────────────────────────│────────────────┘
                                                     │
  External interfaces (outside item):          [Brake System ECU]
  ├── Vehicle CAN bus (speed, yaw rate)         [HMI / Instrument cluster]
  ├── Brake system ECU (receives brake request) [Power supply]
  └── HMI (driver warning display/audio)

  Item definition must specify:
  ├── What the item does (functional description)
  ├── What it does NOT do (exclusions — prevents scope creep)
  ├── External interfaces (inputs/outputs at item boundary)
  └── Assumptions about the operating environment

Exercise 2: ASIL Candidate Pre-Assessment

Markdownasil_pre_assessment.md

# ASIL Pre-Assessment: FCAB System Functions

## Function 1: Emergency Braking Activation
Hazard: Unintended emergency braking at highway speed
- Severity (S): S3 — multiple fatalities possible (rear-end collision)
- Exposure (E): E4 — occurs on highway; continuous exposure
- Controllability (C): C3 — average driver cannot control rear collision
→ ASIL = S3 × E4 × C3 = **ASIL-D**
Safety Goal: "Avoid unintended activation of emergency braking above 5 km/h
             unless object detected with probability > 99%"

## Function 2: Forward Collision Warning (audio/visual)
Hazard: False warning causing driver startle/distraction
- Severity (S): S1 — minor injury possible (distraction)
- Exposure (E): E4 — highway driving continuous
- Controllability (C): C1 — driver easily ignores false warning
→ ASIL = S1 × E4 × C1 = **ASIL-A**
Safety Goal: "Limit false FCW rate to < 1 per 1000 km"

## Function 3: Radar sensor communication loss detection
This is a safety mechanism (not a primary function):
- Derived from: ASIL-D emergency braking function
- ASIL allocated: **ASIL-D** (diagnostic/monitoring path)
- Requirement: "Detect radar communication timeout within 50 ms"

## Notes on Decomposition
- Emergency braking path can be ASIL-D(C) + ASIL-D(C) (redundant channels)
- Warning display path: ASIL-A (much lower than braking path)
- Brake system ECU (external): must accept ASIL-D brake requests

Exercise 3: Safety Plan — Confirmation Measures Table

Markdownconfirmation_measures.md

# Confirmation Measures Plan — FCAB ASIL-D Functions

## Required Confirmation Measures (ISO 26262 Part 2 Clause 6.4)

| ID   | Activity                        | Method    | Independence | Due       | Status  |
|------|---------------------------------|-----------|--------------|-----------|---------|
| CM01 | Item Definition review          | Walkthrough| I1 (peer)   | 2024-03   | OPEN    |
| CM02 | HARA report review              | Inspection | I2 (team)   | 2024-04   | OPEN    |
| CM03 | Safety Goals review             | Inspection | I2 (team)   | 2024-04   | OPEN    |
| CM04 | FSC review                      | Inspection | I2 (team)   | 2024-05   | OPEN    |
| CM05 | TSR review (system)             | Inspection | I1 (peer)   | 2024-06   | OPEN    |
| CM06 | HW FMEA review                  | Inspection | I1 (peer)   | 2024-08   | OPEN    |
| CM07 | SW Safety Requirements review   | Inspection | I1 (peer)   | 2024-07   | OPEN    |
| CM08 | SW Architecture review          | Inspection | I2 (team)   | 2024-09   | OPEN    |
| CM09 | Unit test plan + coverage review| Inspection | I1 (peer)   | 2024-11   | OPEN    |
| CM10 | Safety audit #1 (mid-project)   | Audit     | I2 (team)   | 2024-10   | OPEN    |
| CM11 | Safety audit #2 (pre-release)   | Audit     | I2 (team)   | 2025-02   | OPEN    |
| CM12 | Functional Safety Assessment    | Assessment | I3 (ext)   | 2025-03   | OPEN    |

## Review Criteria
Each review must: (1) confirm all required work products present and complete,
(2) confirm bidirectional traceability, (3) confirm ASIL-appropriate methods used,
(4) produce a review report with open issues tracked to closure.

## Assessor Engagement
External assessor engaged at concept phase to review scope and HARA — not at end.
Assessor attends key milestone reviews (CM02, CM03, CM10, CM11).

Summary

The safety plan is a living document — it must be updated throughout the project as scope changes, schedules shift, and new safety analysis findings emerge. The most common safety plan failure mode is treating it as a one-time document created at project start and never revisited. The confirmation measures table must track actual completion status and review findings, not just planned dates. An auditor or assessor will ask to see the completed review reports referenced in the safety plan — a confirmation measure listed as completed with no corresponding review report is a major finding.

🔬 Deep Dive — Core Concepts Expanded

This section builds on the foundational concepts covered above with additional technical depth, edge cases, and configuration nuances that separate competent engineers from experts. When working on production ECU projects, the details covered here are the ones most commonly responsible for integration delays and late-phase defects.

Key principles to reinforce:

Configuration over coding: In AUTOSAR and automotive middleware environments, correctness is largely determined by ARXML configuration, not application code. A correctly implemented algorithm can produce wrong results due to a single misconfigured parameter.
Traceability as a first-class concern: Every configuration decision should be traceable to a requirement, safety goal, or architecture decision. Undocumented configuration choices are a common source of regression defects when ECUs are updated.
Cross-module dependencies: In tightly integrated automotive software stacks, changing one module's configuration often requires corresponding updates in dependent modules. Always perform a dependency impact analysis before submitting configuration changes.

🏭 How This Topic Appears in Production Projects

Project integration phase: The concepts covered in this lesson are most commonly encountered during ECU integration testing — when multiple software components from different teams are combined for the first time. Issues that were invisible in unit tests frequently surface at this stage.
Supplier/OEM interface: This is a topic that frequently appears in technical discussions between Tier-1 ECU suppliers and OEM system integrators. Engineers who can speak fluently about these details earn credibility and are often brought into critical design review meetings.
Automotive tool ecosystem: Vector CANoe/CANalyzer, dSPACE tools, and ETAS INCA are the standard tools used to validate and measure the correct behaviour of the systems described in this lesson. Familiarity with these tools alongside the conceptual knowledge dramatically accelerates debugging in real projects.

⚠️ Common Mistakes and How to Avoid Them

Assuming default configuration is correct: Automotive software tools ship with default configurations that are designed to compile and link, not to meet project-specific requirements. Every configuration parameter needs to be consciously set. 'It compiled' is not the same as 'it is correctly configured'.
Skipping documentation of configuration rationale: In a 3-year ECU project with team turnover, undocumented configuration choices become tribal knowledge that disappears when engineers leave. Document why a parameter is set to a specific value, not just what it is set to.
Testing only the happy path: Automotive ECUs must behave correctly under fault conditions, voltage variations, and communication errors. Always test the error handling paths as rigorously as the nominal operation. Many production escapes originate in untested error branches.
Version mismatches between teams: In a multi-team project, the BSW team, SWC team, and system integration team may use different versions of the same ARXML file. Version management of all ARXML files in a shared repository is mandatory, not optional.

📊 Industry Note

Engineers who master both the theoretical concepts and the practical toolchain skills covered in this course are among the most sought-after professionals in the automotive software industry. The combination of AUTOSAR standards knowledge, safety engineering understanding, and hands-on configuration experience commands premium salaries at OEMs and Tier-1 suppliers globally.