It is unquestionable fact that killing is a major sin as indicated by the Qur’an and the Sunnah of the Prophet (peace be upon him). It is the most abominable and abhorrent act following shirk (associating partners with Allah in worship.)
Al-Bukhari narrated that the Messenger of Allah (peace and blessings of Allah be upon him) said, “The believer will continue to be encompassed by the mercy of Allah so long as he does not shed blood that is forbidden to shed.”
Concerning this issue, Dr. Monzer Kahf, Scholar in Islamic Economics & a Financial Expert stated that , if out of negligence, a person caused the death of the other by his car , he becomes liable for diyyah. This means that the death was not caused by the deceased himself through suicide intention or actual action on the part of the deceased. So, if is confirmed that it was the car, driven by a person, which killed the others and they had not taken any clear action of suicide (like throwing themselves under the car), such a person is then required to pay their families (appropriate heirs) the diyyah.
In today’s currency, the diyyah varies from one country to another. In Saudi Arabia, they consider it SR 120,000 that I argue as, in fact, it is much smaller than what is intended by the Prophet (peace be upon him) when he made it about 4000 Dirham. After the Prophet’s time and because of a decline in the price of currency, it was raised during Abu Bakr and `Umar several times until it settled at 12,000 Dirham. I should say, in the US and in US Dollars, it is today between US$ 300,000 and 500,000 since 4000 dirhams were equal to about 12 years of gross salary of a normal unskilled person.
Whatever the case may be, diyyah remains the right for this kind of killing that is not intentional and it should be paid for each deceased.
May Allah guide all of us to what pleases Him