The “Core Deaf” (the ones who never, ever have heard a sound) are absolutely petrified of being stopped by the police.
If you know one of these folks, tell them to get a placard that says something like “Deaf driver - can you please write it down for me?”, and have it laminated. It can live (upside down) on the dashboard directly in front of the steering wheel. NOT in the overhead visor (”GUN!”), NOT under the seat (GUN!”) - on the dashboard.
That is good advice