Numbers 35:22-28 "But if without hostility someone suddenly shoves another or throws something at him unintentionally or, without seeing him, drops a stone on him that could kill him, and he dies, then since he was not his enemy and he did not intend to harm him, the assembly must judge between him and the avenger of blood according to these regulations. The assembly must protect the one accused of murder from the avenger of blood and send him back to the city of refuge to which he fled. He must stay there until the death of the high priest, who was anointed with the holy oil.
'But if the accused ever goes outside the limits of the city of refuge to which he has fled and the avenger of blood finds him outside the city, the avenger of blood may kill the accused without being guilty of murder.'
Having said that, I deny that a drunk driving death is unintentional. It's about as unintentional as me pointing a loaded gun at your head and pulling the trigger, then telling the judge I thought the safety was on.