If you mandate noise you will never get silence.
Good. That's an admirable goal. The greater the destructive potential of a vehicle, the more evident it should be. Making cars only evident in the visual spectrum is a poor choice, even at the cost of your evident need to sleep, rest, or otherwise concentrate while near a roadway.
Plus once you get enough cars close together you almost can't distinguish them anyway because it basically becomes white noise.
Not so. There's a reason why bells are more or less constantly rung in China on bicycles; it's not unlike echolocation. Riders advertise their presence for safety purposes.
Just because people have become accustomed to a certain amount of noise is not a credible argument for continuing to emit noise pollution needlessly.
Just because [reason that is not the reason for the argument]... [stuff]. It's not a question about what we are accustomed to. We shouldn't continue to have seat-belts in cars because we're accustomed to them. We should continue to have them because they're a bloody safety feature.
And no, I am not at all concerned about blind or inattentive pedestrians crossing the road in front of me. It's MY responsibility as a driver to drive carefully and watch out for possible road hazards. It is also their responsibility to watch out when crossing the road.
Excellent, let's reduce the bidirectional safety measures because you want to hear your whale-song tranquility CD better. There are situations - real situations - where line-of-sight is blocked but usefully sound is not. You can currently hear cars around a corner, or behind an obstruction, before you step out, peddle out, or potentially make a lane change. Yes, it is everyone's responsibility to "be safe", but audible motor vehicles is a tool that aids in that endeavor.
Hell, people get hit by trains while walking and they make a huge racket and are 100% avoidable by staying off the tracks.
People are occasionally killed in airplane crashes, which are very, very loud, and completely avoidable by walking everywhere instead of flying.
There is simply no good argument for allowing the removal of a useful side-effect, other than your personal tastes. Now, I admit there's a big difference between say, a Harley, or... um... my big-ass V8... and a typical car, in that there is such a thing as simply obnoxious. But silent cars? Bad idea.