Is the husband obligated to pay the blood money for accidental killing after his wife's death in a car accident caused by another vehicle?

If your friend was not at fault or did not cause the accident, then he is not obligated to pay blood money (diyah) or expiation (kaffarah). The expiation and blood money are due from the driver who was at fault. If both were jointly at fault, then the blood money is on their aaqilah (male relatives on the father's side) according to the proportion of their fault, and a full expiation is due from each of them.

The main reasons for error are: 1. Neglect of car maintenance (such as brakes). 2. The driver's condition (such as driving while tired or distracted). 3. Violating traffic regulations.

According to Sheikh Ibn Uthaymeen, car accidents resulting in injuries to passengers who rode by choice fall into four categories: 1. Driver's transgression: Such as excessive speeding or applying brakes forcefully without necessity. 2. Driver's negligence: Such as neglecting to close a door or maintain the car. In these two cases, expiation is obligatory for the driver, which is the freeing of a slave. If unable to find one, then fasting for two consecutive months for each protected soul. He is also obligated to compensate for damaged property, and the blood money is on his aaqilah. 3. Driver's action to avoid danger: Such as swerving to avoid a collision. 4. Without any cause from him: Such as a tire blowout or an unexpected bridge collapse. In these two cases, nothing is obligatory for the driver in terms of expiation or compensation, because he is a trustworthy and benevolent person, or there was no transgression or negligence on his part.

Sheikh Ibn Baz was asked about a man whose car overturned, and his wife died. He replied: "If you did not neglect your driving or your car's requirements, and the accident occurred in a normal and safe driving situation, then nothing is incumbent upon you. However, if it was due to your negligence, then expiation is incumbent upon you, which is the freeing of a believing slave. If you cannot find one, then fasting for two consecutive months, based on the saying of Allah the Almighty: (And it is not for a believer to kill a believer except by mistake. And whoever kills a believer by mistake – then the freeing of a believing slave and a compensation payment presented to his family, unless they remit it as charity. But if he was from a people hostile to you and he was a believer – then the freeing of a believing slave. And if he was from a people with whom you have a treaty – then a compensation payment presented to his family and the freeing of a believing slave. And whoever does not find [one] – then a fast for two consecutive months as repentance to Allah. And Allah is ever Knowing and Wise.) An-Nisa/92. And feeding [the poor] is not sufficient for that."