Leenx
The TMC is the latest in the live traffic management control and if you really want to know more then have a look at the latest Primera or Pathfinder info packs as they have it as an option on the base models.
Tried it around the south west and it dont work too good, not enough traffic apparently. doh !
Its a free 12 month thing then subscription presumably as after the first 12 months you might have been a) able to understand how it works, been able to utilise it at least once to avoid a traffic jam, c) just got used to the incessant interuption of your fav DVD music session.
Good Luck.