alt Hacker NewsI'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).