Apple has come up with a way to allow a self-driving car to communicate much more than lane changing information to other drivers of maneuvers it intends to perform, with the advance warning likely to reduce the possibility of accidents involving both driven and autonomous vehicles.

https://appleinsider.com/articles/18/08/21/apples-project-titan-car-could-warn-you-what-it-is-about-to-do-well-before-it-does-it