NEW YORK – As the HD Radio Alliance unleashes a major campaign to promote its high-definition technology at the North American International Auto Show in Detroit this week, BMW AG says starting this spring the factory-installed option will be available in all of its models.

A 15-person HD Radio street team in orange jumpsuits and hats will fan out during the auto show, which opens to the public Jan. 13, distributing VIP cards.

The cards will allow recipients to register their phone numbers in a raffle to win an HD Radio converter that changes conventional AM/FM radio into an HD digital radio.

The alliance also is sponsoring five mobile billboards that will cruise Detroit streets promoting HD Radio.

BMW first announced it would offer HD Radio in the fall of 2005 in 7-Series and 6-Series vehicles. Last June, the German auto maker expanded HD Radio availability to 5-Series cars and recently said the ’07 3-Series convertible will offer the option, which has a suggested retail price of $500.

There currently are more than 1,100 radio stations across the country broadcasting digital signals, says iBiquity Digital Corp., which invented the system.

More than half of the FM stations broadcasting the digital signals offer its multicast feature, which theoretically allows up to seven different channels in the bandwidth of one FM station. WAMU in Washington, D.C. currently offers three channels on its 88.5 bandwidth.

Several other auto makers are gearing up to offer HD Radio beginning next year, iBiquity says.