Why would anyone bother to create a road that plays music, as a vehicle passes over it?

Watch this video and you will see that, as a car is being driven around 55 MPH (88 km/h) the occupants can hear the “music” of the “William Tell Overture” (by Gioachino Rossini).

Here is a news item, regarding that same stretch of highway, in Lancaster, California.

I guess maybe my question should have been, “What were they thinking?” (Supposedly, the Japanese are doing the same thing.)

What’s going on?