Driverless cars

I heard they had been introduced onto the roads of Milton Keynes just how safe are these driverless cars though what would happen if there was a system malfunction or crash with the computer what about if a person was able to hack into the system and control the car also from what I have read they may not work as well in challenging weather conditions also who has liability if there is a accident also they maybe a increase in radiation which could cause further sickness is this just another way of stopping people from thinking for themselves and controlling peoples lives telling us what to put on our face what to put into our bodies when we can go out where we can go and now how to drive.