Let me preface this with this is my opinion ONLY. I like intelligent discourse so if you don't agree please let me know with some civility.
I see the comments and have discussions all the time about louder exhausts and how they make safer bikes. Sadly this is situational at best and with sound proofing in cars I highly doubt it makes much difference.
Then you get into the aspect of the Doppler Effect those cars in front of you aren't hearing anything until you are next to them, which is debateable due to soundproofing in the car as well as the blue tooth headset in their ear and/or the radio cranked to a volume described as AHHH MY EARS BLEED!!! Also factor in climate control and the fan's white noise and the fact glass can block certain registers of sound. Your left with the fact that most cars won't hear your exhaust until you are right next to them and minimally at best.
So if you love how your exhaust sounds - AWESOME!
If you think/ or know it improves performance and that is what you want - AWESOME!!!
If you think the traffic ahead of you or directly to your left or right can hear it more than what ever they are focusing on you - MAYBE
If your exhaust is louder than a police, ambulance or fire engine siren - my advice is wear hearing protection.
Physics is against the loud pipes saves lives thing. Environmental controls and comfort in cars is against this also. As an example think about how long it took to hear that ambulance behind you now factor in your exhaust probably isn't as loud. Now think of you on a motorcycle with a loud exhaust directly under your right ear and wearing a helmet... your actually less likely to hear things than a driver.
I love hearing different exhausts but louder pipes won't help you as much as riding defensively.
Be safe fellow rider and enjoy your ride. I was having a conversation at happy hour last night (diet coke and lime all the way and free wings
). I wish I had saved the napkin drawings of sound wave demonstration. Was talking to some Harley/Vulcan riders I ran into last night who saw me pull in on the Versys and started chit chatting with me about how quiet my bike was compared to theirs. I managed to score a free burger out of the deal, especially when I kept refusing beers.
Just imagine some big bearded beefy pirate making WOOOOO noises in a bar to demonstrate sound level differences by walking to and from us. By the way they were great to talk to and had some tips for my ride trip next year on some places to stop along the way for scenery pictures.