Being I've been with NoiseFreeAmerica for many years, they've given me updates, over the years, on what cities are doing to tackle loud stereo's in cars, which are referred to as Noise Terrorists.
In Oregon, if you "show off" a loud stereo in your car, it's a $1500 fine, and in some jurisdictions the fines have escalated to $2500, and in some jurisdictions, they can impound the vehicle, and in some places in the Deep South, they can even throw you into jail. The decibel levels from some of these car stereo's can reach 140 decibels, beyond the threshold of pain. But they're quite easy to get out of your neighborhood, providing they don't park in a garage.
In Edmonton, Alberta they now have Noise Radar, similar to Speed Radar, whereas you can get a ticket in the mail for having a loud muffle or loud stereo in your car.
The last mayor of NYC, I understand, went on a campaign to make NYC the quietest big city in the country. Car alarms are illegal in NYC, due to excessive vandalism of people annoyed with them waking them up in the middle of the night. Boom cars, no way! And I saw the signs on my last trip to NYC: $350 fine for honking your horn in a residential neighborhood. And I understand police sirens were banned, but ambulance/fire truck sirens were not banned.
People don't realize that Noise is a health hazard. Go ahead an laugh: Extra loud noises can even trigger heart attacks in some people.