A self-driving Uber SUV struck and killed a pedestrian in Tempe, Arizona. It was in autonomous mode at the time of the collision, with a vehicle operator behind the wheel. Uber has suspended testing of its self-driving cars.
http://money.cnn.com/2018/03/19/technology/uber-autonomous-car-fatal-crash/index.html [cnn.com]
https://www.nytimes.com/2018/03/19/technology/uber-driverless-fatality.html [nytimes.com]
I couldn't find any good analysis of the liability situation here.