I've been riding daily/year round for 30 years. I've ridden loud bikes and quiet ones. The effect on road users- no difference. The effect on animals varies, turkeys don't care either way, wild hogs and bears run away from the sound. Deer, when startled by the noise tend to run across the road in front of you (not real bright animals). I have one road on my commute to work where I'll see deer an average of 3 times a week all year round. I've had 2 deer vs bike collisions on that commute. The first time, the exhaust on my Ducati Hypermotard startled a doe and she ran across the road directly into the side of my bike. The second time, I had stopped my BMW R1200CL (with the stereo blasting) to watch 3 does who had just crossed the road and darted into the woods. I then heard a crashing noise as a buck in rut hurdled the bushes and hit me helmet to antlers. On the Zero, I've ridden within 20 feet of a deer grazing at the side of the road and it not even take notice of me. Granted, these are anecdotal examples but they're my personal experience. Do with it as you wish.