I have tried bells, whistles, horns, yelling and all manner of noises and nothing worked. That is until I barked at a squirrel that was in the middle of my lane, sitting there, dumb struck and not knowing what to do.
I don't know what possessed me, but I barked loudly several times. It scared the little critter out of his reverie, and he sped out of my path.
It works on birds, bunnies, and rodents. I don't know how it would work on a raccoon, but I think it might work.
My friend's wife saw me one day barking at a rabbit, and, as Dances With Wolves was making the circuit on cable TV, she got the bright idea to give me the Indian name Barks At Bunnies. I told her I also barked at squirrels, mice, chipmunks, etc., so she changed to to Barks at Rodents.
Does not, however, work with dogs!