Am I obligated to fast or feed the needy on behalf of those who died in a car accident that I did not cause, and is their blood money incumbent upon me?

There is no blood money (diyya) or expiation (kaffarah) upon you as long as you are certain that you did not cause the death of your two friends, nor did you fall short in fending off harm from them, and that the accident was caused by the fugitive. For what cannot be guarded against incurs no liability, and all such liability falls upon the perpetrator if found.