Must I pay blood money for a motorcycle rider who collided with me, then crashed into a pole and died, knowing that the traffic report attributed the error to him? And will I be held accountable for that on the Day of Judgment?

If you were not the cause of the accident, as confirmed by the investigation of the competent authority (traffic police), then you are not liable for blood money (Diyyah), expiation (Kaffarah), or sin, Allah willing. This is because liability only arises from direct action or causation.