If it's your car, you are at fault.
There are examples of situations where a car producer/manufacturer was at fault for accidents, caused by bad software. The question is where that line will be in the myriad of situations that will be more complex due to the the introduction of automation.The control system itself is then a part of the car, which will dramatically increase the likelihood that it is at-fault in the case of an accident. It presumably would have to be audit-able in the case of an accident to identify whether it made the 'correct' decisions or not, adding additional legal and technical complexity.
If privately owned, would there be regular sensor cleaning/calibration tasks that need to be met before the manufacturer is deemed liable? What about tire pressure?
There will be a lot of factors that could go into deciding whether the user or manufacturer was at fault in the case of an accident that simply wouldn't be a problem now, because the user of the vehicle is also the one responsible for maintenance.