A Japanese engineer by the name of Shizuo Shinoda accidentally scraped some markings into a road with a bulldozer and drove over them, and realized that it was possible to create tunes depending on the depth and spacing of the grooves. In 2007, the Hokkaido National Industrial Research Institute refined Shinoda’s designs to create the Melody Road. They used the same concept of cutting grooves into the concrete at specific intervals and found the closer the grooves are, the higher the pitch of the sound; while grooves which are spaced farther apart create lower pitched sounds. Today, musical roads are known to exist in six countries: Denmark, Japan, South Korea, the United States of America, Mexico and San Marino.
The first known musical road, the Asphaltophone, was created in October 1995 in Denmark, by two Danish artists. The Asphaltophone is made from a series of raised pavement markers, spaced out at intermittent intervals so that as a vehicle drives over the markers, the vibrations caused by the wheels can be heard inside the car.