When considering whether they're net saving lives we are now doing so from the starting point that self driving cars presently have a worse fatality record per real world mile driven than humans, including the portion of miles driven by humans who are unfit to drive or wilfully reckless.
Self driving cars can also be tested in real life environments with safety drivers behind the wheel whose own driving shortcomings are unlikely to coincide with software error. This is believed from the OEM's own telemetry to have prevented several accidents with early generation Waymo
(Edit: and apparently one was present in this vehicle and was unable to prevent the accident)
Of course, there's a PR benefit of taking the drivers out of the car at this stage of their development, and it appears this has taken priority...
Self driving cars can also be tested in real life environments with safety drivers behind the wheel whose own driving shortcomings are unlikely to coincide with software error. This is believed from the OEM's own telemetry to have prevented several accidents with early generation Waymo (Edit: and apparently one was present in this vehicle and was unable to prevent the accident)
Of course, there's a PR benefit of taking the drivers out of the car at this stage of their development, and it appears this has taken priority...