Tony George, once the most powerful man in IndyCar racing, exited the auto racing business Thursday by suspending operations of the Vision Racing team in the Indy Racing League.

Driver Ed Carpenter, George's stepson, was among about 15 people put out of work by the move from a man who spent two decades as president of the famed Indianapolis Motor Speedway.

The decision follows George's resignation from the board of directors of the family firm that owns the IndyCar Series and the Speedway earlier this month following his ouster as Speedway and Series president last June.

It was George who used the drawing power of the Indianapolis 500 to form the IRL as a breakaway series in 1996 and assume control of IndyCar racing in 2008 in a merger following a 12-year civil war in US open-wheel racing.

George told employees he lacked sufficient sponsorship to continue operations. The 2010 IndyCar season opens in Brazil in March with testing to begin in late february.