When handling critical software and hardware, for example automated cars, it should be the case that it's never ever the sole responsibility of a single individual. People make mistakes, and will always do. There should be a lot of safety mechanisms existing to ensure nothing critically bad ever happens due to a bug. If this is not the case, then management is to blame, and even the state, for not ensuring high quality of critical equipment.

When something like that does happen, it is very hard to know the measure of responsibility every entity holds. This will most certainly be decided in court.