Andy Fixmer:

Gaining access to listeners in cars is a key part of Pandora’s strategy to win more of the $15 billion market in local radio advertising in the U.S. More than half of radio listening occurs in automobiles.

While Apple’s built-in voice controls, called Eyes Free Siri, will navigate to any application, it defaults to its own programs when a user makes a music request, Greenfield wrote.

“Apple is clearly favoring their native music app with radio based commands,” Greenfield said. “If you were in Pandora and used Siri with the command ‘play Jazz Radio’ it would literally stop Pandora, open up iTunes Radio and starts playing the iTunes Radio Jazz station.”

Greenfield says he expects Google Inc. (GOOG) to take a similar approach to Apple in marrying hardware and software design when it debuts an YouTube music service in the year ahead.