Is blood money obligatory for someone who caused the death of his friend in a car accident, despite not remembering the details of the accident and the traffic report proving him at fault?

If the driver took the necessary safety precautions, then what occurred that he could not prevent is not held against him, and there is no blood money (diyya) or expiation (kaffara) due from him. However, if he was negligent, then he is responsible, and expiation is due from him, and the blood money is due from his 'aqila (male kin). Accordingly, if the traffic report proves that the accident was due to your negligence and that you were the cause, then the blood money is due from your 'aqila and the expiation is due from you.