# HARA (ISO 26262)

> Conduct a Hazard Analysis and Risk Assessment for road vehicles per ISO 26262. Covers hazard identification, S/E/C classification, ASIL determination, safety goals, and ASIL decomposition validation for redundant sub-components. Market: Global / Germany.



Tags: Automotive, Functional Safety, ISO 26262, HARA, ASIL, Germany


## Example Prompts

- Perform a HARA for the steering assist function
- Classify this hazardous event and determine ASIL from S/E/C
- Validate that our ASIL D decomposition to B(D)+B(D) is correct
- Draft safety goals and FSRs from the HARA table

URL: https://rakenne.app/skills/hara-iso26262/index.md

Try this skill: https://rakenne.app/a/?skill=hara-iso26262



## Overview

Conduct a complete Hazard Analysis and Risk Assessment (HARA) for road vehicles following ISO 26262:2018 (Part 3). The skill guides you through hazard identification, operational situation and operating mode definition, and the three-dimensional risk classification — **Severity (S)**, **Exposure (E)**, and **Controllability (C)** — to determine the **Automotive Safety Integrity Level (ASIL)** or QM for each hazardous event. It then drafts **Safety Goals** and validates **ASIL decomposition** for redundant sub-components.

ASIL determines the rigor of functional safety activities required across the product development lifecycle (hardware, software, system integration). Getting HARA wrong leads to under-specified safety goals, failed type-approval audits, and liability exposure in case of field incidents.

## When to use this skill

Use this skill when you are:

- **Starting a new HARA** for a vehicle function (steering, braking, powertrain, ADAS, body controls) and need a structured S/E/C classification table with ASIL determination per ISO 26262 Table 4.
- **Validating an existing HARA table** to confirm that all relevant hazardous events and operational situations are covered and ASIL ratings are correctly derived.
- **Drafting Safety Goals (SG)** and Functional Safety Requirements (FSRs) from a completed HARA table as input to the Functional Safety Concept.
- **Validating ASIL decomposition** for redundant sub-components — confirming that decomposed ASIL pairs (e.g., ASIL D → ASIL B(D) + ASIL B(D)) are architecturally valid per ISO 26262-9.
- **Preparing for a TÜV or functional safety audit** and need a complete, traceable HARA record with documented rationale for each S/E/C classification.

Typical users include functional safety engineers, systems engineers, safety managers at automotive OEMs, Tier 1 suppliers, and engineering service providers preparing ISO 26262 certification packages.

## Getting Started

Add your item definition, system description, and any preliminary hazard lists to the project workspace, then activate the *HARA (ISO 26262)* skill. Tell the agent the vehicle function or item under analysis, the target vehicle class (passenger car, motorcycle, truck), and your project phase. The agent will systematically identify hazardous events, define operational situations, and walk through S/E/C classification for each combination.

## Example conversation

> **You:** We need a HARA for the Electric Power Steering (EPS) assist function. Passenger car, highway and urban driving.
>
> **Agent:** Starting with hazard identification for EPS. Key malfunctions to consider: (1) unintended steering torque assist (over-assist), (2) loss of steering assist (under-assist), (3) erratic/oscillating torque. I'll define operational situations: high-speed highway, low-speed urban, parking. For each combination I'll derive S, E, and C values. Ready to classify — shall I use ISO 26262:2018 Tables 2–4?
>
> **You:** Yes. Let's start with unintended over-assist at high speed.
>
> **Agent:** Hazardous event: Unintended high steering torque at highway speed (>100 km/h).
> - S3 (life-threatening / fatal injuries likely if driver loses control)
> - E4 (high probability — highway driving is frequent)
> - C2 (normally controllable — an alert driver can compensate, but not in all cases)
> - **ASIL C** per Table 4.
>
> Safety Goal draft: "The EPS system shall not apply unintended steering torque exceeding X Nm at vehicle speeds above 80 km/h." ASIL C applies to this safety goal. Shall I continue with loss of assist and parking scenarios?
>
> **You:** Also validate our decomposition — we split ASIL C into ASIL A(C) + ASIL B(C) across two independent torque sensor channels.
>
> **Agent:** ASIL C decomposition check: ASIL A(C) + ASIL B(C) — valid per ISO 26262-9 Table 5. The sum satisfies ASIL C provided the two channels are sufficiently independent (no common-cause failures). I'll add a note that independence must be demonstrated in the Dependent Failure Analysis (DFA).

## Output excerpt

Example ASIL determination table entry:

```
============================================================
HARA Table — Electric Power Steering (EPS)
Item: EPS Assist Function | Vehicle Class: Passenger Car
============================================================

Hazardous Event: Unintended high steering torque (over-assist)
Operational Situation: Highway driving (>100 km/h)

  Severity (S):      S3 — Life-threatening injuries likely
  Exposure (E):      E4 — High probability (frequent driving condition)
  Controllability:   C2 — Normally controllable

  ASIL Result:       ASIL C

Safety Goal: The EPS system shall not apply unintended steering
torque exceeding [X] Nm at vehicle speeds above 80 km/h.
Safe State: EPS transitions to reduced-assist mode within [T] ms.

ASIL Decomposition Check (A(C) + B(C)):
  OK: Decomposition is valid per ISO 26262-9 Table 5.
  NOTE: Independence of torque sensor channels must be demonstrated
        in the Dependent Failure Analysis (DFA) — ISO 26262-9 Clause 7.
============================================================
```



---

Back to [Skill Library](https://rakenne.app/skills/index.md)