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.