What is the ruling on the fasting of drivers whose driving led to the death of two people in each car they were driving?

If the driver exerted his utmost effort to avoid the collision, and was not the cause of it, and did his best to secure his car and adhere to traffic rules, then neither expiation (kaffarah) nor blood money (diyah) is incumbent upon him, due to his lack of negligence. The principle states: "That which cannot be avoided entails no liability." However, if he was negligent in any of the aforementioned, then expiation and blood money are incumbent upon him, because it is an accidental killing that the driver directly committed. It is best to refer to the competent courts.