Sirens are an unfortunate reality, but the reason they're so loud is because most cars have a ton of sound-proofing. I'm sure you know this, but you can hear sirens blocks away when they're trying to alert a driver... maybe 20 metres in front of them to move out of the way?
As for excitable drunks, I think there are places where that's a constant problem, but again, this isn't constant and permanent. Traffic noise and airplanes are pretty constant though - I live on what should be a pretty quiet stretch of land but the local stroad always has at least a few really loud cars in the wee hours of the morning. The rest of the day it's just lots of regular cars making a lot of noise as cars are want to do. At least with the excitable drunks they don't make noise all hours of the day, since they have to sleep or be drinking at some point!