Talk:Traffic Message Channel

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Where can I get a list of available TMC messages from Navteq or Teleatlas?

Answer: From none of these. These two companies do just provide digital maps that include references to the location codes used by TMC. The possible TMC messages are compiled fro these location codes plus event codes and other information. See the TMC-Standard ISO 14819-1.[1]

As the event is coded during transmission with 10 bit, there are 2048 different event elements possible (of which until now only about 1400 are defined). They are ranging from traffic sitatuations (like "traffic jam ahead") to information about traffic related events like weather ("strong wind") and public events announcements ("parade"). Due to the fact that you can add quantifiers (like "2 km traffic jam ahead") and/or to combine 2 and more of these events (like "parade, traffic jam expected"), in practice you can combine these building blocks to create quite a big number of possible traffic messages.

The list of events is part if the ISO standard ISO 14819-2 [2]

For each country you can define different location lists, in each of which about 60 000 location codes are avalable. (the location code is coded as a 16-bit numberduring transmission). The structure and the possibilities of the location tables are described in the ISO standard 14819-3 [3]

A good source of information is the TMC-Forum. [4] Members have easy access to location tables and event list (in the different languages).

[edit] UK national coverage

• The private company iTIS Holdings provides a commercial TMC service iTMC in the United Kingdom. It is broadcast nationally on Classic FM.
• RAC Live operated by RAC Trafficmaster Telematics (RTT) a 50-50 joint venture between RAC Motoring Services and Trafficmaster also operates a national service. It uses 3 commercial radio broadcasters, GWR, Capital radio and Chrysalis who together ensure reception across mainland Britain

Neither of these statements are correct. Neither provide a national service, there are large areas where none of these stations can be received. --jmb 01:10, 28 May 2007 (UTC)

Also, while I have excellent Classic FM coverage (including all RDS information) my TomTom devices tells me it cannot find any TMC carrier. Are there gaps in the relay of TMC information as well as coverage issue ? —Preceding unsigned comment added by 86.155.98.215 (talk) 00:25, 12 January 2008 (UTC)