[Collision of two cars and the death of two persons in each of them]

The answer – and Allah is the One who grants success – is that if both drivers shared in the fault, then each driver is liable for what has perished of lives and property in the other car.
If, however, the fault that caused the collision was on the part of one of them alone and not the other, then the one at fault is liable for what was lost in both cars, and nothing is due from the other driver.

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