Hazard Analysis & Risk Assessment (HARA) + Safety Goals
ISO 26262 (automotive functional safety) Part 3 – HARA produces
ASIL ratings that drive everything downstream. Structure also maps
to IEC 61508 (SIL) hazard & risk analysis.
| Field | Value |
|---|
| Item (system) | name – defined per Part 3 item definition |
| Analysis date | YYYY-MM-DD |
| Team | safety engineer, system owner |
1. Operational situations & hazards
| ID | Hazardous event | Operational situation | Possible consequence |
|---|
| HE-01 | Unintended acceleration | highway driving | collision at speed |
| HE-02 | Brake assist loss | emergency braking | extended stopping |
| HE-03 | Steering torque fault | low-speed parking | minor collision |
2. ASIL determination (S x E x C)
| Event | Severity S (0-3) | Exposure E (0-4) | Controllability C (0-3) | ASIL |
|---|
| HE-01 | S3 | E4 | C3 | D |
| HE-02 | S3 | E2 | C2 | B |
| HE-03 | S1 | E4 | C1 | A |
S: severity of harm · E: exposure probability · C: controllability.
QM = quality-managed (below ASIL A) – no safety requirements needed.
3. Safety goals (per ASIL C/D event)
| SG | Event | Safety goal statement | ASIL | Safe state | Fault-tolerant time |
|---|
| SG-01 | HE-01 | prevent unintended acceleration | D | power limited | N ms |
| SG-02 | HE-02 | maintain minimum braking | B | degraded braking | N ms |
4. Functional safety requirements (derived)
| FSR | Goal | Requirement | Mechanism |
|---|
| FSR-01 | SG-01 | redundant torque monitoring | dual-channel compare |
| FSR-02 | SG-01 | safe-state transition ≤Nms | watchdog + cutoff |
5. Verification & confirmation
- Confirmation measures required by ASIL level (independence levels
I0-I3 for reviews, testing)
- Safety case: argument that residual risk is tolerable