Someone mentioned loud horns on pb.
Guess what, there are a good number of very loud horns and they're not very expensive. Farbin 150db 150db is loud, right, louder than a rock concert. And cheap, about $30 bucks and not hard to install. They work on all sorts of vehicles, cars, rvs, motorcycles, etc etc.
https://www.walmart.com/ip/FARBIN-Compact-Air-Horn-with-Compressor-Electric-Car-Horn-12V-150db-Super-Loud-train-horns-kit-for-trucks/594217146