What must the driver do for God to forgive him after he hit a boy with his car, causing his death, as a result of exceeding the speed limit by 30 kilometers per hour?

We understand that you were driving your car at 80 in a place where the speed limit is 50, and you hit a child who then died. This is an accidental killing, which obligates you to pay blood money (diyya) to the child's guardians, unless they pardon it. You are also obligated to offer expiation (kaffara), which is the freeing of a believing slave. If you cannot find one, then you must fast for two consecutive months.