ISO 26262-4:2018

INTERNATIONAL ISO
STANDARD 26262-4
Second edition
2018-12
Road vehicles — Functional safety —
Part 4:
Product development at the system
level
Véhicules routiers — Sécurité fonctionnelle —
Partie 4: Développement du produit au niveau du système
Reference number
©
ISO 2018
© ISO 2018
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ii © ISO 2018 – All rights reserved

Contents Page
Foreword .v
Introduction .vii
1 Scope . 1
2 Normative references . 2
3 Terms and definitions . 2
4 Requirements for compliance . 2
4.1 Purpose . 2
4.2 General requirements . 2
4.3 Interpretations of tables . 3
4.4 ASIL-dependent requirements and recommendations . 3
4.5 Adaptation for motorcycles . 4
4.6 Adaptation for trucks, buses, trailers and semi-trailers. 4
5 General topics for the product development at the system level . 4
5.1 Objectives. 4
5.2 General . 4
6 Technical safety concept . 5
6.1 Objectives. 5
6.2 General . 6
6.3 Inputs to this clause . 6
6.3.1 Prerequisites . 6
6.3.2 Further supporting information . 6
6.4 Requirements and recommendations . 6
6.4.1 Specification of the technical safety requirements . 6
6.4.2 Safety mechanisms . . 7
6.4.3 System architectural design specification and technical safety concept . 9
6.4.4 Safety Analyses and avoidance of systematic failures . 9
6.4.5 Measures for control of random hardware failures during operation .11
6.4.6 Allocation to hardware and software .11
6.4.7 Hardware-software interface (HSI) specification .12
6.4.8 Production, operation, service and decommissioning .12
6.4.9 Verification .13
6.5 Work products .14
7 System and item integration and testing .14
7.1 Objectives.14
7.2 General .15
7.3 Inputs to this clause .15
7.3.1 Prerequisites .15
7.3.2 Further supporting information .15
7.4 Requirements and recommendations .15
7.4.1 Specification of integration and test strategy .15
7.4.2 Hardware-software integration and testing .17
7.4.3 System integration and testing .19
7.4.4 Vehicle integration and testing .21
7.5 Work products .24
8 Safety validation .24
8.1 Objectives.24
8.2 General .24
8.3 Inputs to this clause .25
8.3.1 Prerequisites .25
8.3.2 Further supporting information .25
8.4 Requirements and recommendations .25
8.4.1 Safety validation environment .25
8.4.2 Specification of safety validation .25
8.4.3 Execution of safety validation . .26
8.4.4 Evaluation .26
8.5 Work products .27
Annex A (informative) Overview of and workflow of product development at the system level .28
Annex B (informative) Example contents of hardware-software interface (HSI) .30
Bibliography .34
iv © ISO 2018 – All rights reserved

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
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organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: www .iso .org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 22, Road vehicles Subcommittee, SC 32,
Electrical and electronic components and general system aspects.
This edition of ISO 26262 series of standards cancels and replaces the edition ISO 26262:2011 series of
standards, which has been technically revised and includes the following main changes:
— requirements for trucks, buses, trailers and semi-trailers;
— extension of the vocabulary;
— more detailed objectives;
— objective oriented confirmation measures;
— management of safety anomalies;
— references to cyber security;
— updated target values for hardware architecture metrics;
— guidance on model based development and software safety analysis;
— evaluation of hardware elements;
— additional guidance on dependent failure analysis;
— guidance on fault tolerance, safety related special characteristics and software tools;
— guidance for semiconductors;
— requirements for motorcycles; and
— general restructuring of all parts for improved clarity.
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