From Spluch:

With 68 percent of highway accidents in Korea caused by inattentive, sleeping or speeding drivers, the Korean Highway Corp., as well as the Hokkaido Industrial Research Institute in Japan, came up with the idea of musical road surfaces to keep motorists entertained but also to reduce their speed and help them stay alert. On Korean highways, the song of the streets is the simple, yet sweet “Mary Had a Little Lamb.”

Beethoven’s Ninth, anyone? How about the intro from Sweet Child of Mine?