Seems like a lot of cars, here in Washington State, don't have mufflers. There are a lot of loud cars. I guess we don't do the yearly smog check when people had to bring their cars in to check for pollution, including noise pollution. Maybe different in California. That was dropped some years back, here in Washington, as I have heard. Enforcement of noise ordinances is lax.
Most cars are pretty quiet, but there are quite a few loud ones. Lots of revving of engines as well. A macho thing.