Personally, given this video, I'd still be totally comfortable with a self driving car on the road with no safety driver (who clearly didn't make a difference here anyway, not that they could have).
But as others have pointed out, it's hard to tell what the driver could have seen just from the dashcam video, which for starters, has a much less dynamic range than human vision. Because in the accident scene photos/videos, the ambient street light is much more visible [0]. I'm guessing driving down that Arizona road at night can't possibly be as pitch dark as the camera shows it, given how that area seems to be used for entertainment venues/festivals.
[0] http://sanfrancisco.cbslocal.com/2018/03/19/uber-self-drivin...