Overview
ISO/TS 18234-8:2012 - TPEG1-CTT (Congestion and Travel Time) specifies a method for delivering congestion and travel time messages within the TPEG (Transport Protocol Experts Group) generation‑1 binary data format. It defines how traffic status and travel time information is encoded in a byte‑oriented stream so it can be carried over a variety of bearers (terrestrial/satellite Digital Multimedia Broadcasting, Internet, etc.). The application is designed for language‑independent delivery and presentation (text, audio or graphics) and is assigned Application ID (AID) = 0004 within the TPEG suite.
Key topics and technical requirements
- Message architecture
- TPEG1‑CTT messages comprise three main containers: Message Management Container, Application Event (Status) Container, and the TPEG‑Location Container (location details specified in ISO/TS 18234‑6).
- Message management includes mandatory elements, date/time handling and message lifecycle controls.
- Status and event encoding
- The specification defines a Status Container for congestion status descriptions and the coding of CTT information (status, qualifiers, quantifiers).
- Location referencing
- Supports TPEG location referencing methods (map‑based and human‑readable) via the TPEG‑Location Container to precisely identify links and routes affected.
- Tables and semantics
- Uses hierarchical, word‑oriented TPEG CTT tables (e.g., Congestion Type Table, Congestion Tendency Table) to standardize vocabulary and coding.
- Byte‑oriented stream format
- Messages follow the TPEG1 byte stream framing and semantics defined in ISO/TS 18234‑2 (SSF).
- Conformance and normative references
- Requires conformance with TPEG SSF and SNI parts (ISO/TS 18234‑2 and ISO/TS 18234‑3) and is intended for proven broadcast and IP delivery systems.
Applications and who uses it
- Practical uses
- Real‑time dissemination of road congestion, travel times and status (e.g., ferry operation, bridge status) to navigation systems, in‑vehicle infotainment, mobile apps and digital broadcasters.
- Enables multi‑platform distribution (DMB, satellite, Internet) and machine‑readable delivery for automated traffic management or routing agents.
- Typical users
- ITS vendors, navigation and map providers, automotive OEMs, broadcasters, mobile service operators, traffic control centers and application developers building traffic/travel services.
Related standards
- ISO/TS 18234‑1: TPEG1 Introduction, numbering and versions (INV)
- ISO/TS 18234‑2: Syntax, Semantics and Framing Structure (SSF)
- ISO/TS 18234‑3: Service and Network Information (SNI)
- ISO/TS 18234‑6: Location referencing (TPEG‑Loc)
- Other TPEG application parts (RTM, PTI, PKI, TEC, CAI) listed in the 18234 series
Keywords: ISO/TS 18234-8:2012, TPEG1-CTT, TPEG, congestion and travel time, traffic and travel information, binary data format, message management, location referencing.
Open preview (PDF)Intelligent transport systems — Traffic and travel information via transport protocol experts group, generation 1 (TPEG1) binary data format — Part 8: Congestion and Travel Time application (TPEG1-CTT)