Cars too quiet and too loud.

Apparently there is a move afoot to make the Prius noisier, out of a concern for pedestrians and bikers. As a Prius owner, I am not opposed to some increase in the sound of a Prius in the interest of general safety. But why just focus on quiet vehicles as a danger to pedestrians and bikers? Loud exhaust systems must make regular exhaust systems at least as hard for pedestrians and bikers to hear as a Prius is. When laws against loud pipes are actually enforced, I will gladly tie the proverbial bell on my car.