What is the expiation for the death of an elderly widowed woman in a car accident caused by quicksand that led to the loss of control of the vehicle?

If you caused an accident that led to a person's death due to speeding, a vehicle malfunction, or inattentiveness, then you must offer expiation by fasting for two consecutive months and repent to Allah. Your 'aqilah (male relatives on your father's side) must pay the blood money, based on the Almighty's saying: "And whoever kills a believer unintentionally - then the freeing of a believing slave and a compensation [blood money] presented to his family, unless they remit it..." until His saying: "And he who finds not [the means to do so] - then a fast of two consecutive months as repentance to Allah. And Allah is ever Knowing and Wise." However, if you were not the cause and adhered to safety regulations, then there is nothing upon you.