Lots of motorcycle riders claim this: "Loud pipes save lives".
In my anecdotal experience, as the owner of both noisy and quiet motorcycles, there is very little truth to that. My noisy motorcycles have just as many "Sorry mate, I didn't see you" incidents as my quiet ones. On the other hand, looking like you might be an evil baby-eating biker (cruiser-style bike, black leather, open face helmet with a beard and sunglasses, blatantly disregarding road rules) does seem to have a probably statistically significant reduction in other road users treating you badly. People don't "not see you" or "not hear you" they judge you as not being a danger to them - perhaps subconsciously, perhaps consciously, but I have strong suspicion that lots of people do look and see you, but their heads categorise you as either "just a tiny fucking motorcycle, I'm insured so I don't care if they bounce off my car" or "I'd better not annoy _that_ guy, he might reach through my window and rip my head off and then go home and murder my family and pets".
I could _maybe_ see an argument that especially quiet vehicles (electric for sure, but a lot of modern ice cars as well) might improve pedestrian safety with a little bit of "fake engine noise" being projected at low speeds where pedestrians are likely to be around, but 105db straight through pipes do not improve anyone's safety at 25mph+ in my experience, they just annoy people. (And I say that somewhat hypocritically, as the owner of a Ducati with aftermarket and louder than stock pipes, but which fall a long way short of 100+db straight through Harley Davidson pipes.)