What should I do about a sheep head-on collision incident that occurred 12 years ago, given my inability to determine the accident's location or the sheep's owner to pay compensation?

A Muslim should not drive his car above the permitted speed limit, as this exposes himself and others to danger. Whatever property of others is damaged, whether intentionally or by mistake, you must return its value or an equivalent. Intention and error are the same when it comes to people's property. Therefore, you must search for the owner of the sheep and hand over its value to him. If the owner cannot be found, its value should be given as charity on his behalf. If he is found later and approves what was done, then you are absolved. Otherwise, the price must be paid. As for unintentionally killing animals, there is no sin or expiation for it, because Allah has removed from the Ummah the burden of error and forgetfulness. However, one must drive responsibly to avoid a recurrence of this.