Car makers will get data they can use to simulate and test their self-driving cars.

But car makers will also get full GPS traces - showing where you live, where you work, where you shop and every time you speed. And they'll probably get what phone was seen on bluetooth, how many seats were occupied, and what radio station was listened to. All identifiable by vehicle, and very close to identifiable by driver.

Will they manage to make good use of the former, while avoiding the temptation to monetise the latter?

Of course, Google gets a bunch of data from Android users already, so one might very well argue most users aren't concerned about such things.