Quoted from the Official GT6 website
Do you have any plans on using this feature?
This may not be available on launch but it opens up the possibilities of creating circuits based on anywhere you can go with a mobile device (presumably). It could be your route to work, a street course you've imagined in your neighbourhood or even a local race track! Of course I expect there will be few environments to choose from to make the track playable but that didn't stop users from dreaming up creating circuits for GT5 back in the day.Gran Turismo said:Course Maker
This feature, available at a later stage through an update, will allow you to create your own custom tracks that can be driven in the game. Additionally, in another update we will add the possibility to generate a track by capturing the GPS coordinate data of a mobile app while you are driving that course. This GPS-generated tracks will be available in the game as playable content.
Do you have any plans on using this feature?