The RAB believes that technology enhancements and more choice will lead to the increase in listeners.
The research also cited the growth of devices such as mobile phones that include radio and features such as rewind radio as factors behind the predicted growth.
Michael O'Brien, client services director at the RAB, said: "Digital radio is providing more for both the listener and the advertiser. There is no doubt that this will help the medium to continue to grow. This is a very exciting time for radio, both the commercial sector and the BBC.
Speakers at the seminar included: Simon Nelson, controller of BBC Radio and music interactive; Jo Hamilton, head of research at BBC Radio and Music; Andy Tilley, partner at The Ingram Partnership; and Professor John Naughton, the chairman of RAB-eye.
The RAB/BBC event follows encouraging news for commercial radio, which showed ad revenues rise 7.5% in the first quarter. Total revenue to the end of March reached £150.9m.
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