Road Rage Murder or Self-Defense Shooting?

On a regular Saturday morning drive, a father of two becomes involved in an altercation at an intersection; believing his life is threatened, he shoots and kills the other motorist; the Prosecution say the deceased posed no physical threat; was the accused justified in his actions, or is he guilty of "bringing a gun to a fistfight"? In a legal first, an AI-generated version of the victim speaks in court.