I live in Phoenix, Arizona and these are all around. Honestly I feel like the future everyone will have Waymo type services and no one will own cars or even need to learn how to drive one. Who needs to worry about car repairs insurance etc.
I've rode in them a few times, fell asleep even. I trust a Waymo more than most human drivers. Best test of its capabilities I saw was when school let out and the side road was covered in kids and parents and cars in random spots waiting for people. It stayed in the "lane", no lane lines, and calmly navigated forward as people gave it space. I was in the car the whole time. Still there are some issues to be ironed out, but ultimately I don't think I have ever had a bad riding experience.