Accidents happen because of the unexpected, no matter how smart the system is there will always be something that has not been anticipated by the developers/engineers so I expect the introduction of self driving cars to be something of an evolution, ie someone gets killed, the cause is investigated, the software solution is determined and downloaded globally overnight. This is why extensive tests are being carried by the manufacturers - to try and capture as many potential issues/ failings prior to going public.
I envisage a problem with this system is, the present Motor Manufacturers resistance to admitting major safety issues with their vehicles ( Bad Press?) and their further reluctance to issue recall notices (costs) . Test drivers are being sacrificed during the development testing process, these are admittedly at the pointy end - but and this is a big BUT . The Test Drivers are highly trained professional drivers, if these guys are crashing - what training is it possible to put together which will reduce the risk !
