What is the legal ruling regarding an incident that led to the death of seven people after a fuel truck driver overturned on them, knowing that he was imprisoned, paid the blood money, and the victims' families waived their personal right against him? And is a religious expiation (kaffarah) obligatory upon him, such as freeing a slave or fasting?

The blood money (Diyah) and expiation (Kaffarah) resulting from car accidents depend on the extent of the driver's negligence. If there was no negligence on the part of the driver (such as exceeding the speed limit or not slowing down in dangerous areas), and the accident was beyond his control, then there is no Diyah on his 'Aqilah (male agnatic relatives responsible for paying blood money) and no Kaffarah upon him. However, if there was negligence, then Kaffarah is obligatory upon him for each deceased person, and their Diyah is obligatory upon his 'Aqilah.