That looks like something that might be used to bring down small commuter aircraft, birds, and other low flying critters.
Sometimes, people and their need for loud noise just plain baffles me. These will be the same crotchety old farts who can't hear a fiddlesticking sound later in life and complain about not being able to hear to everyone they can get to listen. In my books, the owner of that vehicle just won a Darwin Award.