Humming Road - a waste in America

It's an interesting thought - a road that humms a tune so you wont be bored or feel bad for humming a song as you try to pay attention to the road.
But I have a few thoughts:
1- ofcourse it has to be in japan - becuase in america, who can hear the road over my MP3 player....
2- if I could hear the song humming, it would probably be late at night and it would put me to sleep [ not good ].
3- With all the pot holes I encounter - no wonder everything sounds like hip hop....lol