I'm willing to bet 99.99% of the time you hear music from outside a car it's not due to someone being hard of hearing, unless they caused that issue themselves by listening to music too loud.
However, if you are hard of hearing to the point where you are actually disturbing others, I would recommend headphones.
It is not generally legal to drive while wearing headphones. In some US states it is specifically banned, and in many others you will get pulled over for distracted driving. (The thinking is partly because it makes it more difficult to hear emergency vehicle sirens).
Background noise makes it difficult for the hard of hearing to listen to conversation.
If we cared more for the hard of hearing we would reduce music volumes and make restaurants quieter. Our society doesn't care even though it pretends to.
