[notacoward]

I looked into this claim a while ago, and actual research on the subject is equivocal at best. Most often, drivers don't even notice the sound on an already-noisy road or highway, through deliberately sound-dampening windows, over music and conversation, etc. Even if they notice, they don't necessarily know where it's coming from. Even if they know where it's coming from, it doesn't necessarily influence their actions. Some people who say "loud pipes save lives" are just fooling themselves. More often, people who say it know it's not likely to be true, but they say it anyway to put a veneer of respectability over the fact that they like the sound and don't care if it's annoying to others.