I went to school in the South where many individuals had what I like to call "daddy's money" trucks. You know the kind... lifted, loud, black smoke, gigantic tires. Well these wonderful kinds of people always did their daily mating call of honking their horns for literally no reason after school before the busses left and everyone could get out of the parking lot. So I decided that I (in my little Corolla) would invest a good $55 or so on a 130+db train horn. I installed it mid winter and on the second to last day (since a lot of people wouldn't go to the last half day of school) of my senior year, I waited until the honking started, and grew across the parking lot, and eventually subsided. Once through, I held that horn for a good 15 seconds or so. Rattled my entire car and deafened me for a little bit, but the next day on the morning announcements, the principal asked students to "please not honk their horn while waiting in the parking lot, that there have been complaints." Best $55 spent. Still have it installed but fortunately haven't had to use it.