Overview
SIST EN ISO 14819-2:2021 (ISO 14819-2:2021) is part of the ISO 14819 series for Intelligent Transport Systems (ITS). It specifies the standardized Event and Information Codes used to encode traffic and travel messages for the Radio Data System - Traffic Message Channel (RDS‑TMC) using the ALERT‑C protocol. Part 2 defines the canonical “Events List” (and related supplementary and forecast lists) that enables densely coded, language‑independent traffic messages to be transmitted over FM radio subcarriers.
Key technical topics and requirements
- Event List database: A structured database of event phrases in a technical language (CEN‑English) with associated binary/decimal codes used in RDS‑TMC message payloads.
- Code format and semantics: Each event entry includes the decimal equivalent of the binary event code, a nature flag (N) indicating Information, Forecast (F), or Silent (S), and a quantifier (Q) field referencing quantifier definitions.
- Update classes & terminal message management: Events are grouped by update classes to support terminal handling and lifecycle of messages, as defined in ISO 14819‑1.
- Supplementary and forecast lists: Separate standardized lists for additional contextual information and predicted events (forecast events).
- Language and unit independence: Event definitions are metric by default, with recommended conversions and non‑metric (imperial) alternatives provided in informative annexes (A–D). Presentation to end users may be localized without changing encoded meaning.
- Conformance and references: Intended to be used together with ISO 14819‑1 (ALERT‑C protocol/message structure), ISO 14819‑3 (position/place coding), and ISO 14819‑6 (optional encryption). Normative external reference: IEC 62106 (RDS specification).
- Edition changes: The 2021 third edition supersedes the 2013 edition, adding new events and a “phased‑out codes” indicator among editorial clarifications.
Practical applications and who uses it
- Traffic message providers & broadcasters: Standard way to encode events for RDS‑TMC services delivered over FM radio.
- Navigation and telematics vendors: In‑car navigation systems and mobile apps decode ALERT‑C messages to display live traffic, route guidance, and alerts.
- Map data and location service providers: Integrate standardized event/quantifier semantics to ensure consistent user messages across regions.
- Road authorities and traffic management centers: Publish interoperable traffic bulletins for regional and cross‑border distribution.
- Device manufacturers and ITS integrators: Implement terminal message management and presentation logic based on update classes and supplementary information.
Related standards (must-read)
- ISO 14819‑1 - ALERT‑C coding protocol and message structure (required)
- ISO 14819‑3 - Position and place coding for ALERT‑C
- ISO 14819‑6 - Conditional access/encryption for traffic messages
- IEC 62106 - Radio Data System (RDS) specification
Keywords: RDS‑TMC, ALERT‑C, ISO 14819‑2:2021, event codes, traffic message coding, intelligent transport systems, traffic and travel information.
