A planned Gran Tourismo Sport Beta won’t be happening anymore according to game creator, Kazunori Yamauchi.
The reason the beta was cancelled is so that the development team at Polyphony could concentrate on getting the actual game out this year.
In an interview with Yamauchi he commented
It’s required that in order to do an open beta we have to create a proper master for it, and considering the release timing that we announced, we decided that we just don’t have enough time to do two gold masters for the game. By omitting that, it saves us about three months of time.