Musical road

A musical road is a road, or part of a road, which when driven over causes a tactile vibration and audible rumbling transmitted through the wheels into the car body in the form of a musical tune.

Musical roads are known to exist in eight countries: Denmark, Japan, South Korea, the United States of America, China, San Marino, Taiwan, and Ukraine.

The first known musical road, the Asphaltophone, was created in October 1995 in Gylling, Østjylland, Denmark, by Steen Krarup Jensen and Jakob Freud-Magnus, two Danish artists. The Asphaltophone is made from a series of raised pavement markers, similar to Botts' dots, 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.

In Japan, Shizuo Shinoda accidentally scraped some markings into a road with a bulldozer and drove over them, and realised that it was possible to create tunes depending on the depth and spacing of the grooves. In 2007, the Hokkaido National Industrial Research Institute, which had previously worked on a system using infra-red lights to detect dangerous road surfaces, 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.

There are multiple permanently paved 250 m stretches of Melody Roads. The first ones built included one in Hokkaido, another in the town of Kimino in Wakayama where a car can produce the Japanese ballad "Miagete goran yoru no hoshi wo" by Kyu Sakamoto, one in Shizuoka Prefecture on the ascending drive up Mount Fuji, and a fourth in the village of Katashina in Gunma, which consists of 2,559 grooves cut into a 175 m stretch of existing roadway and produces the tune of "Memories of Summer". The roads work by creating sequences of variable width groove intervals to create specific low and high frequency vibrations. Some of these roads, such as one in Okinawa that produces the Japanese folk song "Futami Jowa", as well as one in Hiroshima Prefecture, are polyphonic, with different sequences of rumble strips for the left and right tires so that a melody and harmony can be heard.

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