Radio One Agrees to Encode its Radio Stations for the Arbitron Portable People Meter Ratings System in Philadelphia and Los Angeles

NEW YORK, January 5, 2007– Arbitron Inc. (NYSE: ARB) announced today that Radio One (NASDAQ: ROIAK and ROIA), the largest radio broadcasting company that primarily targets African-American and urban listeners, has agreed to encode its radio stations in Philadelphia and Los Angeles for the Arbitron Portable People Meter^TM audience measurement services.

An encoding agreement is separate and distinct from any agreement to subscribe to the Portable People Meter ratings services.

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