What is "autofahrer-rundfunk-informationssystem"

Autofahrer-Rundfunk-Informationssystem (ARI, German for: Automotive-Driver's-Broadcasting-Information) was a system for indicating the presence of traffic information in FM broadcasts used by the German ARD network of FM radio stations from 1974. Developed jointly by IRT and Blaupunkt, it indicated the presence of traffic announcements through manipulation of the 57 kHz subcarrier of the station's FM signal.

ARI was rendered obsolete by the more modern Radio Data System and the ARD stopped broadcasting ARI signals on March 1, 2005.