DD CEN ISO/TS 18234-4:2006 - Page 4

Traffic and travel information (TTI). TTI via transport protocol expert group (TPEG) data-streams. Road traffic message (RTM) application | Status: Current

1 Scope This document establishes the method of delivering Road Traffic Messages within a TPEG service. The TPEG-RTM application is designed to allow the efficient and language independent delivery of road information directly from service provider to end-users. The information provided relates to event and some status information on the road network and on associated infrastructure affecting a road journey. For example, limited information about abnormal operation of links in the network may be included, such as ferries, lifting-bridges, etc. The term “application” is used in TPEG specifications to describe specific applications, such as in this case the Road Traffic Message application, which comprises three information containers: the Message Management Container, the Application Event Container and the TPEG-Location Container. The first two Containers are fully described herein and the TPEG-Location Container is described in CEN ISO/TS 18234-6. Each TPEG application (e.g. TPEG-RTM) is assigned a unique number that is called the application identification (AID). An AID is defined whenever a new application is developed. The AID is used within the TPEG-Service and Network Information Application (CEN ISO/TS 18234-3) to indicate how to process TPEG content and allows routing of data to an appropriate application decoder. AID = 0001 is assigned to the TPEG-Road Traffic Message application, described in this specification. A hierarchical methodology has been developed to allow the creation of messages from a set of TPEG-RTM tables, which are essentially word oriented and cover most needs. Many of the TTI descriptive words, in the TPEG-RTM tables, were obtained from the DATEX dictionary (ENV 13106), which embodies European TTI knowledge of the last ten years or more, including a deconstruct of the phrase oriented RDS-TMC events list (EN ISO 14819-2). These TPEG-RTM tables (essentially word oriented data object dictionaries) comprise a wide ranging ability to describe a TTI event and some status information, introducing new precision in a number of areas such as “vehicle types”, “positional information on the carriageway” and “diversion routing advice”.

NOTE Explicit backwards compatibility with the RDS-TMC events list (EN ISO 14819-2) could not be achieved since some “update classes”, such as “29 Reference to Audio Broadcasts” and “30 Service Messages”, fall outside the TPEG-RTM remit.