We somehow managed to get Gran Turismo creator Kazunori Yamauchi to slam on his brakes for a moment today and talk to us about his flagship racing franchise. According to the Polyphony Digital boss, his studio is focusing a majority of its efforts on Gran Turismo 5 Prologue. In fact, he confirmed that the proper, disc-based Gran Turismo 5 might not even roll out before 2010.

In the meantime, Polyphony will continue to expand Prologue with additional cars, tracks, and features. Yamauchi couldn't speak to specific plans, but mentioned that an new update is planned for the near future.

With all of the work his company is putting into the next console GT installment, Yamauchi tells us that it hasn't forgotten the long-delayed Gran Turismo 4 Mobile for PSP. He confirms that the game – originally announced at E3 2004 – is still actively in development, although it isn't planned for release until after GT5. That would be 2011 for those with pen and calendar in hand.

This article was originally published on Joystiq.

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