I thought I had loud car and truck horns, but lately I have found them to be useless. Having been very nearly killed by a zonked-out ear-bud wearing dipshirt driving an ambulance [!] plus trying to miss the hoards of brainbucket-wearing Quad riders infesting the public backroads around my boondoc home every summer I need something a hell of a lot louder.
Just the other day I was driving down a gravel road towards town. Out of a sideroad roared a dirtbike [no plate of course so he obviously didn't have to pay attention to the stop sign.] He looked left and right and seemed to think he could get out in front of me. Which he did. He was followed by a guy on a quad we can call F. Tard who only looked left 'cuz that was the direction his bud went. Never looked my way at all. And, he too did the "rolling stop" manuever.
Then he proceeded down the road at a screaming 19 KPH, swerving violently left and right to avoid whatever. I amused myself by blowing the horn repeatedly to get him to pull right and allow me to pass, but he heard nothing. I'll be polite and blame this on the full brain bucket he was wearing and not some demented death wish. I could go on and on about such nitwits, I have lots of examples, but what about a real loud horn? I know there are lots of louder than stock horns, and I've had some but I don't think they will work on zombies.
I need painfully loud. Something that can blow the eyes out of a snake.