They have been under testing for years now. 2,660 pedestrians were killed by cars driven by people, with driving licences... Till we know what actuality happened, you might want go google some of your questions, as there are many answers out there if you take a look.

Here, let me get you started.
https://medium.com/waymo/waymos-fleet-reaches-4-million-self-driven-miles-b28f32de495a