For musicians fearful of air bags,

1. There are earphones that block sound. I use them using a table saw. It turns the howling screech into a growl. I don't think these would be a good idea to wear while driving a car. Maybe couldn't hear sirens, honks, police whistles, etc..

2. There are electronic noise-cancelling earphones that block sound even more. Same problem.

3. There are earplugs that block loud noises, but pass softer sounds. People use these on firing ranges and hunting. I imagine they wouldn't be a problem driving a car. I don't know. Maybe check your local laws and/or ask a few cops (uh, bobbies? for you Brits)

My personal solution is to avoid driving in times and places of heavy traffic, but Your Mileage May Vary