I have a toy plane and toy quadcopter, also known as drones. I fly them (tell them to fly themselves?) at an athletic park, in the middle of several soccer fields. Surrounding the soccer fields are open, undeveloped land. Sometimes the wind picks up unexpectedly or there is a mechanical problem and they crash. Then I have to go find it in the trees or whatever.
If I chose to send my drone (toy) flying around a busy parking lot and a gust of wind sent it crashing into a baby stroller, I would be responsible. I sent the drone flying, I'm responsible for any consequences. (On the other hand, if I use it to assist in a search and rescue mission, somebody may give me credit for doing that.) Anyway, I bought it and chose a time and a place to put it in the air, and where to direct it to go. I hold the "off" switch and the "abort, come home" switch. It's my responsibility.
Also, if my drone suddenly flies off course at full speed and crashes into something fragile AND other owners of the same model report the same type of malfunction, I'm going to ask the manufacturer to reimburse me for any damages I had to cover. There are implied warranties they would be in breach of.
I see "self driving" cars exactly the same. If I buy one, I can let it drive on a road in Arizona that's straight for 45 miles at a time and I only see another car once every 20 minutes, or I can turn on "self driving" mode on a busy freeway. I can keep my hands on the wheel and my eyes on the road ready to respond to emergencies or I can choose to watch Youtube in busy traffic. I'm responsible for how I use the device (via my insurance company, whom I pay to absorb the risk). If the car suddenly accelerates at full throttle in a traffic jam, I'm going to hold the manufacturer responsible for the defect, but as far as other drivers are concerned, my car hit them. My car is my responsibility.