Westwood One is an American radio network that was based in New York City. At one time, it was managed by CBS Radio, the radio arm of the CBS Corporation, (Columbia Broadcasting System) and Viacom (1971–2005) and was later purchased by the private equity firm, The Gores Group. Due to purchases, mergers and other forms of consolidation in the 1980s and 1990s, at one time or another, it had ownership stakes in or syndication rights to some of the most famous brands in network radio, including CBS, NBC, Mutual, CNN, Fox and Unistar. The company was one of the largest producers and distributors of radio programming in the United States. It broadcast entertainment, news, weather, sports, talk, and traffic programming to about 7,700 radio stations across the United States. The company was the top provider of local traffic reports in the US through its subsidiaries, Metro Networks, Shadow Broadcast Services, SmartRoute Systems, and Sigalert.com. Westwood One also offers weather services; originally using Accuweather, Westwood switched to The Weather Channel in 2009.