The ARI Traffic Broadcast System

[Old Sparky]

This is/was a system used in Germany, Austria, and possibly Switzerland in the 1980s to relay information about roadworks, diversions, accidents, etc. over FM radio via coded transmissions carried on  a subcarrier along with the normal programmes.  Car radios had a decoder built in, which, when selected, allowed those broadcasts to be heard, and, on roadside signs, the frequency of the local ARI-equipped station, together with a regional code letter, was displayed.  This system was never adopted in the UK, and UK market versions of Blaupunkt ARI-equipped radios didn't have the decoders fitted.   As far as I know, ARI was discontinued in Europe after RDS became widely available.  Can anyone confirm this?

[Terry]

On 1st March 2005, according to Wikipedia: https://en.wikipedia.org/wiki/Autofahrer...ionssystem

Don't forget the BBC's Carfax system!

This was a trial that started in 1979/80 and operated on 500kHz (formerly a maritime distress frequency).

From memory, I think there were 4 synchronised transmitters around London, where the trials were carried out. I think the idea was that, based on relative signal strengths, the special decoder would only switch on if the traffic information was relative to your location.

[Old Sparky]

This was as I thought, Terry. In fact I informed someone with a Blaupunkt Radio that the ARI system was (a) Never used in the UK, abd (b) is obsolete, As to the BBC 'Carfax' system, I remember that being trialled, althiough, IIRC, they used 557kHz for at least some of the test transmissions. This is of course within the MW (AM) Broadcast band, unlike 500kHz, so the decoders could have been incorporated in normal MW Radios, although Carfax was never put into regular use.