SIST-TS CEN ISO/TS 24315-3:2025

Intelligent transport systems - Management of electronic traffic regulations (METR) - Part 3: System of systems requirements and architecture (SoSR) (ISO/TS 24315-3:2025)

This document defines the end-to-end requirements for the entire management of electronic traffic regulations (METR) system of systems (SoS). This document introduces the reference architecture used by subsequent parts.
NOTE            The operational concept for METR is provided in ISO/TR 24315-2.[9]

Intelligente Verkehrssysteme - Management von elektronischen Verkehrsregularien (METR) - Teil 3: System von Systemanforderungen und Architektur (SoSR) (ISO/TS 24315-3:2025)

Systèmes de transport intelligents - Gestion des règles de circulation sous forme électronique - Partie 3: Exigences et architecture pour le système des systèmes (ISO/TS 24315-3:2025)

Inteligentni transportni sistemi - Vodenje elektronskih prometnih predpisov (METR) - 3. del: Sistemske zahteve in arhitektura (SoSR) (ISO/TS 24315-3:2025)

General Information

• Status: Published
• Public Enquiry End Date: 09-Sep-2025
• Publication Date: 12-Nov-2025
• ICS: 03.220.20 - Road transport
• ICS: 35.240.60 - IT applications in transport
• Technical Committee: ITC - Information technology
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 29-Oct-2025
• Due Date: 03-Jan-2026
• Completion Date: 13-Nov-2025
• Ref Project: CEN ISO/TS 24315-3:2025 - Intelligent transport systems - Management of electronic traffic regulations (METR) - Part 3: System of systems requirements and architecture (SoSR) (ISO/TS 24315-3:2025)

Overview

CEN ISO/TS 24315-3:2025 - Intelligent transport systems (ITS): Management of electronic traffic regulations (METR) - Part 3: System of systems requirements and architecture (SoSR) defines end-to-end requirements for a METR system-of-systems (SoS) and introduces the reference architecture used by subsequent parts. Published by CEN with ISO/TC 204 collaboration, this Technical Specification sets the structural, information and interface expectations needed to manage electronic traffic regulations consistently across jurisdictions and ITS deployments. The operational concept is provided in ISO/TR 24315-2.

Key topics and technical requirements

The document organizes requirements across functional, information and architectural views. Major technical topics include:

• System-level requirements for an integrated METR SoS covering end-to-end flows and conformance.
• Input and output information flows, including:
  • Legal rules (regulatory content and updates)
  • Coordination messages between authorities
  • Discrepancy reports and Traffic Control Device (TCD) status
  • Audit and adaptation information
• Functional requirements such as rule verification and METR information storage.
• ITS station unit requirements (applicable station/unit behaviours), addressing:
  • Support services, timeliness and filtering
  • Open specification, backwards/forward compatibility, and language neutrality
• Information model expectations including a feature catalogue, information content, metadata, observable transport-rule attributes and auditing attributes.
• Actor responsibilities: obligations for rule makers, users, implementers and auditors (e.g., rule maintenance, pre-travel acquisition, mapping and discrepancy identification).
• Reference architecture for the METR SoS (logical/physical views and traceability conventions).

Practical applications

This Technical Specification is designed to enable interoperable, auditable and scalable electronic traffic regulation systems. Practical uses include:

• Designing and implementing national or regional METR platforms that distribute legal traffic rules and dynamic restrictions
• Integrating traffic control devices (TCDs), traffic management centres and vehicle ITS stations
• Ensuring data models, metadata and auditing support for enforcement and legal traceability
• Specifying message/interaction requirements for vendors of ITS units, roadside equipment and backend systems

Who should use this standard

• Road authorities and transport policymakers implementing electronic traffic regulation
• ITS system architects and implementers developing METR solutions
• Software and hardware vendors (TCDs, in-vehicle systems, back-office platforms)
• Urban planners, integrators and auditors who require interoperable architecture and traceable regulatory data

Related standards

• ISO/TR 24315-2 (METR operational concept) - referenced for operational context
• Other parts of ISO/TS 24315 series and ITS standards coordinated by ISO/TC 204 and CEN/TC 278

Keywords: Intelligent transport systems, METR, electronic traffic regulations, ISO/TS 24315-3:2025, system of systems, reference architecture, ITS interoperability, traffic control devices, metadata, auditing.

Standards Content (Sample)

SLOVENSKI STANDARD
01-december-2025
Inteligentni transportni sistemi - Vodenje elektronskih prometnih predpisov
(METR) - 3. del: Sistemske zahteve in arhitektura (SoSR) (ISO/TS 24315-3:2025)
Intelligent transport systems - Management of electronic traffic regulations (METR) - Part
3: System of systems requirements and architecture (SoSR) (ISO/TS 24315-3:2025)
Intelligente Verkehrssysteme - Management von elektronischen Verkehrsregularien
(METR) - Teil 3: System von Systemanforderungen und Architektur (SoSR) (ISO/TS
24315-3:2025)
Systèmes de transport intelligents - Gestion des règles de circulation sous forme
électronique - Partie 3: Exigences et architecture pour le système des systèmes (ISO/TS
24315-3:2025)
Ta slovenski standard je istoveten z: CEN ISO/TS 24315-3:2025
ICS:
03.220.20 Cestni transport Road transport
35.240.60 Uporabniške rešitve IT v IT applications in transport
prometu
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEN ISO/TS 24315-3
TECHNICAL SPECIFICATION
SPÉCIFICATION TECHNIQUE
October 2025
TECHNISCHE SPEZIFIKATION
ICS 03.220.20; 35.240.60
English Version
Intelligent transport systems - Management of electronic
traffic regulations (METR) - Part 3: System of systems
requirements and architecture (SoSR) (ISO/TS 24315-
3:2025)
Systèmes de transport intelligents - Gestion des règles Intelligente Verkehrssysteme - Management von
de circulation sous forme électronique - Partie 3: elektronischen Verkehrsregularien (METR) - Teil 3:
Exigences et architecture pour le système des systèmes System von Systemanforderungen und Architektur
(ISO/TS 24315-3:2025) (SoSR) (ISO/TS 24315-3:2025)
This Technical Specification (CEN/TS) was approved by CEN on 2 October 2025 for provisional application.

The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to
submit their comments, particularly on the question whether the CEN/TS can be converted into a European Standard.

CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS
available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in
parallel to the CEN/TS) until the final decision about the possible conversion of the CEN/TS into an EN is reached.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN ISO/TS 24315-3:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (CEN ISO/TS 24315-3:2025) has been prepared by Technical Committee ISO/TC 204
"Intelligent transport systems" in collaboration with Technical Committee CEN/TC 278 “Intelligent
transport systems” the secretariat of which is held by NEN.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO/TS 24315-3:2025 has been approved by CEN as CEN ISO/TS 24315-3:2025 without any
modification.
Technical
Specification
ISO/TS 24315-3
First edition
Intelligent transport systems —
2025-10
Management of electronic traffic
regulations (METR) —
Part 3:
System of systems requirements
and architecture (SoSR)
Systèmes de transport intelligents — Gestion des règles de
circulation sous forme électronique —
Partie 3: Exigences et architecture pour le système des systèmes
Reference number
ISO/TS 24315-3:2025(en) © ISO 2025

ISO/TS 24315-3:2025(en)
© ISO 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
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ISO/TS 24315-3:2025(en)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms . 1
5 Overview . 2
5.1 METR purpose .2
5.2 METR scope .3
5.3 Management of electronic traffic regulations (METR) overview .3
5.3.1 Functional view .3
5.3.2 Physical view .4
5.4 Assumptions and dependencies .8
5.4.1 Assumptions .8
5.4.2 Dependencies .9
5.5 Traceability conventions.9
5.6 Naming conventions .11
5.7 Traceability and conformance .11
6 System of systems requirements .11
6.1 General .11
6.2 Input requirements . 12
6.2.1 Information flow: legal rules . 12
6.2.2 Information flow: coordination . 12
6.2.3 Information flow: discrepancy information . 13
6.2.4 Information flow: traffic control devices (TCD) status .14
6.3 Output requirements . 15
6.3.1 Information flow: audit information . 15
6.3.2 Information flow: coordination .16
6.3.3 Information flow: information.16
6.3.4 Information flow: information for adaptation .18
6.4 Functional requirements . . 20
6.4.1 Verification of METR rules . 20
6.4.2 METR information storage requirements . 20
6.5 Applicable intelligent transport system (ITS) station unit requirements .21
6.5.1 Support services .21
6.5.2 Timeliness . 23
6.5.3 Filtering . 23
6.5.4 Open specification . 23
6.5.5 Backwards compatibility .24
6.5.6 Forward compatibility .24
6.5.7 Language neutral .24
6.6 Information requirements .24
6.6.1 General .24
6.6.2 Feature catalogue .24
6.6.3 METR information .24
6.6.4 Information content . 25
6.6.5 Information meta-data . 26
6.6.6 Observable transport rule attributes . 26
6.6.7 Additional transport rule attributes .27
6.6.8 Auditing attributes . 28
6.7 Efficient exchange constraint . 28
7 Actor responsibilities .28

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ISO/TS 24315-3:2025(en)
7.1 Rule maker responsibilities . 28
7.1.1 Maintain rules . 28
7.1.2 Define location accurately . 28
7.2 User responsibilities . 28
7.2.1 Acquire rules before travelling. 28
7.2.2 Identify necessary rule criteria . 28
7.2.3 Obtain necessary supporting data . 28
7.2.4 Process rules . 29
7.2.5 Identify discrepancies . 29
7.2.6 Mapping . 29
7.2.7 Determine user's location . 29
7.2.8 Determine environmental conditions . 29
7.3 Implementer responsibilities . 29
7.4 Auditor responsibilities . 29
8 System-level reference architecture .29
8.1 Overview . 29
8.2 Physical view . 30
8.2.1 Mapping to functional view . 30
8.2.2 Centralized information distribution service package .31
8.2.3 Localized information distribution . 36
8.2.4 Discrepancy management . 40
8.2.5 Auditing service package . 44
8.2.6 Service registration and discovery . 46
8.2.7 Security enrolment and credentials management .47
8.2.8 Core authorization . 48
8.2.9 System monitoring . 49
8.2.10 Physical objects . 50
8.2.11 Information flows .52
8.2.12 Cybersecurity overview . 58
8.3 Enterprise view.59
8.3.1 Overview .59
8.3.2 Enterprise objects . 63
8.3.3 Agreements and expectation definitions .70
8.3.4 Role definitions . 73
8.3.5 Resources . 73
9 Variables . 74
9.1 General .74
9.2 catalogueUpdateInterval . .74
9.3 criteriaLatencyTime .74
9.4 distributionResponseTime .74
9.5 informationRefreshDuration . .74
9.6 metrRecoveryTime .74
9.7 metrResponseTime . 75
9.8 metrUpdateCycle . 75
9.9 metrUpTimePercent . 75
9.10 provisionLatency . 75
9.11 subscriptionRefreshTime . 75
9.12 translationUpdateInterval . 75
Annex A (informative) Conformance . 76
Annex B (normative) Diagram conventions .78
Annex C (informative) Possible deployments of role-based architecture .83
Bibliography .93

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ISO/TS 24315-3:2025(en)
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 committee
has been established has the right to be represented on that committee. International 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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of 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 www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 204, Intelligent transport systems, in
collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/TC CEN/
TC 278, Intelligent Transport Systems, in accordance with the Agreement on technical cooperation between
ISO and CEN (Vienna Agreement).
A list of all parts in the ISO 24315 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

v
ISO/TS 24315-3:2025(en)
Introduction
0.1  System overview
The ISO 24315 series on the management of electronic traffic regulations (METR) is intended to provide
users access to geo-specific, trustworthy, timely, authoritative, machine-interpretable, traffic and transport
related rules enacted by jurisdictional entities, including those who define rules for campuses (i.e., private
grounds). This is conceptually shown in Figure 0-1.
Figure 0-1 — Management of electronic traffic regulations (METR) concept
0.1.1  Purpose
METR is designed to assist developers and manufacturers of driving automation systems (i.e., automation
Levels 1 to 5) and driver information systems (including those at automation Level 0) to electronically
obtain traffic rules to better enable:
a) interacting safely with other road users;
b) following instructions from law enforcement organizations, and those authorized to direct traffic;
c) maintaining smooth and safe flow of traffic; and
d) complying with other rules enacted to support legislative policies (such as environmental protection,
noise, manage height and weight restrictions, and societal aspects such as market days, fiestas,
[1]
pedestrian zones, etc.).
METR is designed to provide a reference framework for the trustworthy distribution of electronic versions
of legal traffic rules, however content and application of the traffic rules is outside of the scope of the METR
standards and specifications.
0.1.2  Flow of information
The general flow of METR information is illustrated in Figure 0-2 and subsequently described.

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ISO/TS 24315-3:2025(en)
Key
a METR starts with rule makers defining and enacting rules that are relevant to transport users.
b Each legal rule is translated into a METR rule, which is a secure, standardized electronic representation that
includes a digital signature of the rule signing organization.
c METR rules are collected for a geographic area(s) and specific scope(s).
d Rules are distributed to METR users based on their needs.
e METR users become aware of the METR rules, verify their authenticity, and respond appropriately.
f As needed, METR users can submit discrepancy reports to a discrepancy handler for investigation and
correction.
Figure 0-2 — Management of electronic traffic regulations (METR) flow of information
0.1.3  Graphical overview
Figure 0-3 provides an overview of the data and devices included within the scope of the METR environment.

vii
ISO/TS 24315-3:2025(en)
Key
A freight rules
B kerbside usage rules
C ride sharing rules
D micromobility rules
E VRU rules
F public transport rules
G rules for automated driving systems
H driving rules
I lane use rules
J public-area mobile robot rules
K road work rules
L pre-announced rules with subset of either emergent rules or supporting data or both
M either emergent rules or supporting data, or both
1 various communications and network infrastructure
2 roadside communication unit
3 METR user system
Figure 0-3 — Management of electronic traffic regulations (METR) streetscape
0.1.4  Rule distribution
Electronic traffic rules and their distribution have three orthogonal characteristics that are often confused
with one another.
a) Electronic rules can be pre-announced (i.e., known and publicized well in advance of the user's need)
or emergent (i.e., publicized and needed while previously obtained pre-announced rules are still
considered fresh).
b) Electronic rules can be distributed through a wide-area distribution mechanism or a local distribution
mechanism.
c) Electronic rules can be pulled by users well in advance of their need or pushed to users as special
conditions necessitate.
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ISO/TS 24315-3:2025(en)
It is expected that the characteristics of METR users and the limitations on data capacities for local
distribution mechanisms mean that virtually all persistent rules will be pre-announced and distributed from
a wide-area distribution source, likely using a pull mechanism. However, any emergent rule that is activated
while previously distributed pre-announced rules are still considered fresh necessitates a push mechanism,
often from a local distribution source. Those two combinations are only typical use cases and that METR
supports every possible combination of these three characteristics and addresses how discrepancies can be
reported and resolved.
In addition, supporting data can provide context to the rules and can be transmitted by wide-area
communication systems, roadside units, other vehicles, or on-board devices.
The rules cover virtually any rule related to surface transport systems; the graphic depicts rules for
freight vehicles, kerbside usage, ride sharing, micromobility operations, vulnerable road users (VRUs),
public transport usage, driving (i.e., human-in-the-loop, including driver support systems, which represent
Levels 1 and 2 of automation), Automated driving systems (ADS) (i.e., automation Levels 3 to 5), lane usage,
public-area mobile robots (PMRs), and road works. This information must be available and conveyed to all
transport users including nomadic devices, PMRs, and vehicles equipped with driving automation systems
(i.e., Levels 1 to 5 of automation). Although not shown in the diagram, METR is also intended to be flexible
enough to support rules relating to the use of ferries, passenger rail (e.g., trams, subways, and inter-city
rail), and off-road environments.
0.2  Framework adaptation
METR is defined through the ISO 24315 series, which provides a comprehensive framework for the
interoperable digitalization, distribution, and management of electronic traffic regulations. This framework
will be defined at a relatively high-level and will support both regional adaptation and customization, as
well as the use of non-METR protocols and data formats, as depicted in Figure 0-4.
Figure 0-4 — Three-tier framework
The first set of ISO documents of the ISO 24315 series provide a framework based on the ISO-specified
[2]
systems engineering methodology as defined by ISO/IEC/IEEE 29148, and consist of a vocabulary, a
concept of operations, a reference architecture, and requirements for the METR system of systems (SoS).
Subsequent documents in the ISO 24315 series define requirements for each component system within

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ISO/TS 24315-3:2025(en)
the METR SoS and other requirements common to all component systems. The ISO 24315 series promotes
semantic interoperability but necessitates interpretation and adaption for regional use to provide complete
interoperability (i.e., including syntactic interoperability).
Each region (e.g. EU, Japan, Korea) customizes (e.g. extends and adapts) the ISO 24315 series based on their
specific needs and environment, as necessary to provide cross-border interoperability within their region.
The METR reference architecture is refined to provide regional implementation guidance. For example, in
Europe, METR can eventually become part of the national access point (NAP). Furthermore, non-METR data
[3] [4] [5] [6] [7] [8]
formats including TN-ITS, DATEX-II, TPEG2, TransModel, TMDD, and WZDx can be refined to
support METR requirements or used as-is to deliver METR information to the extent that the data can be
supported (i.e., non-METR distribution). The preferred solution is to update these formats to conform to the
full set of METR trustworthiness requirements.
Translating and adapting international standards and regional interoperability agreements is achieved at
the national level and can even be done at local levels. Operations, funding and governance are determined
nationally, locally, or both. Legal implications of electronic rules provided through METR are defined
nationally or locally. Many places start this digitalization of the rules at an informative supplemental level,
rather than as regulatory.
0.3  Document overview
The METR provides trustworthy, authoritative, machine-interpretable, transport-related rules for using
the road network. The purpose of this document is to define formal requirements for the METR SoS and to
introduce the reference architecture used by subsequent parts.
[2]
The requirements are provided in a format that is consistent with the guidance provided by ISO 29148 for
a system requirements document.
[9]
The operational concept for METR is provided in ISO/TR 24315-2.
This document has been developed in coordination with many experts from countries around the world. It is
designed to be sufficiently generic to be applicable to any national or regional authority that wishes to adopt
its processes.
System developers and system operators within authorities that adopt the METR model are advised to
become familiar with this document and use it as their guide in operations.

x
Technical Specification ISO/TS 24315-3:2025(en)
Intelligent transport systems — Management of electronic
traffic regulations (METR) —
Part 3:
System of systems requirements and architecture (SoSR)
1 Scope
This document defines the end-to-end requirements for the entire management of electronic traffic
regulations (METR) system of systems (SoS). This document introduces the reference architecture used by
subsequent parts.
[9]
NOTE The operational concept for METR is provided in ISO/TR 24315-2.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 21217, Intelligent transport systems — Station and communication architecture
ISO/TS 14812:2022, Intelligent transport systems — Vocabulary
ISO/TS 24315-1:2025, Intelligent transport systems — Management of Electronic Transport Regulations
(METR) — Part 1: Vocabulary
ISO/IEC/IEEE 24765:2017, Systems and software engineering — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC/IEEE 24765, ISO/TS 14812,
ISO 24315-1 apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org
4 Abbreviated terms
For the purposes of this document, the following abbreviated terms apply.

ISO/TS 24315-3:2025(en)
ADS automated driving system
ARC-IT architecture reference for cooperative and intelligent transportation
CCMS cooperative ITS credentials management system
CV connected vehicle
FM frequency modulation
GNSS global navigation satellite system
HTML hypertext markup language
IEC International Electrotechnical Commission
IEEE Institute of Electrical and Electronics Engineers
ISO International Organization for Standardization
ITS intelligent transport systems
MCMC maintenance and construction management centre
METR management of electronic traffic regulations
OBE on-board equipment
OEM original equipment manufacturer
PID personal information device
PMR public mobile robot
RSE roadside equipment
SoS system of systems
SoSR system of systems requirements
SRADS service registration and discovery service
TCD traffic control device
TS technical specification
UN user need
VRU vulnerable road user
WAIDS wide-area information disseminator system
5 Overview
5.1 METR purpose
The ISO 24315 series intends to provide trustworthy transport-related rules in a machine-interpretable
format to transport users.
ISO/TS 24315-3:2025(en)
5.2 METR scope
The METR SoS is designed to provide electronic systems with the rules that travellers are required to follow.
Provision of this rule information can be used directly by the receiving electronic system and can also be
displayed to travellers to confirm which rules are currently relevant. To achieve this, the METR SoS provides
a path and process to distribute the rules defined by rule makers to METR users (e.g. travellers), who are
required to comply with the rules.
Some rules are dependent upon supporting data, which can provide parameters related to a rule (e.g., the
current speed limit for a variable speed limit system) or parameters that activate rules (e.g. the presence
of rain can result in a lower speed limit). The METR SoS is responsible for delivering rules entered by a
translator to (typically mobile) METR user devices. The METR user device is responsible for merging these
rules along with supporting data from other sources (e.g. visually observed rules, current traffic conditions,
and other factors) and providing merged results to the user, as needed. The METR SoS also includes the
ability to report observations from the field back to the central office to ensure that the electronic data store
is consistent with the rules posted in the field.
5.3 Management of electronic traffic regulations (METR) overview
5.3.1 Functional view
Figure 1 summarizes the functional view of METR. It summarizes the functions to be performed and the
data flows associated with each function The diagram conforms to the rules for Yourdon-Demarco data flow
[10]
diagrams, as summarized in Annex B. Depicting all processes and flows on a single diagram is overly
complex. Figure 1 focuses on the main METR processes and flows, while ISO/TR 24315-2:2025, 7.4.2 and
7.4.3 provide a more complete listing as well as a complete description of the diagram.

ISO/TS 24315-3:2025(en)
Key
process (part of METR)
process (external to METR)
data flow
data store
terminator
Figure 1 — Data expectation diagram
5.3.2 Physical view
5.3.2.1 Overview
Figure 2 provides a corresponding physical view diagram of the reference architecture where the METR SoS
is presented as a single physical object. The physical view diagram follows
...