working horn requirement

https://alpha-wiki.win/index.php/How_to_Prepare_for_MOT:_A_Practical_Guide_from_an_Experienced_Mechanic

You pull into the yard just before six, and the old air horn gives a low rumble that shakes the gravel. That working horn requirement isn't about noise for the neighbors; it's a safety check that keeps you from getting flattened by a forklift you didn't hear coming. The sound cuts through engine clatter and radio chatter, a sharp reminder that every second counts when you're moving steel beams around a warehouse, and nobody wants to be the one who missed the warning.