Could you please explain exactly how one can discern that someone is deaf at a distance of > 10m with a degree of certainty whilst categorically ruling out that person is not unstable and exhibiting that by making erratic hand gestures considering your sole evidence to date is that they have been driving erratically with a proven current history of failing to respond to law enforcement instructions.
I'm not saying the cop knew or should have known he was deaf. I'm just highlighting the sheer quantity of verbal demands you need to follow perfectly when getting arrested at gunpoint.