[Two cars collide and a man in one of them dies]

The answer – and Allah is the One who grants success – is that if both cars were in violation of the known rules of traffic and driving, then the blood-money and expiation are upon both of them. Otherwise, it is upon the one who violated the traffic regulations, and not upon the one who did not violate them. For example, if a driver blocks the public road with his car, then he is liable for whatever injuries result from his blocking the road.

Source: Min Thimār al-ʿIlm wa al-Ḥikmah vol.2