Why South Korean Highways Sing

[seti]

Very Coool I wonder what the song is? Lost Highway? Copa Cabanna?

http://abcnews.go.com/WN/Webcast/story?id=3931873&page=1

Engineers in South Korea and Japan have created "singing" highways that
use cars as tuning forks as they barrel along. The songs are intended
to help drivers to stay alert and to remind them to reduce their speed.

American motorists are familiar with the rumble strip. Designed to
alert distracted drivers that they are nearing the edge of the road,
this grooved section of asphalt creates a harsh, thunderous, grating
sound.

Now engineers in South Korea and Japan have one-upped the rumble strip by creating "singing" highways.

Video

Why South Korean Highways Sing

Also known as melody roads, these new thoroughfares use cars,
specifically their tires, as tuning forks to play music as they barrel
along. The musical roads are created by a series of grooves, cut at
very specific intervals, in the surface of the asphalt.

Much like the vibrations and rumbles produced on a bumpy or
poorly maintained street, engineers discovered that different notes
were produced when grooves were placed at certain intervals along the
surface. Depending on how far apart the grooves are, tires moving over
them produce a series of high or low notes, enabling designers to
create a distinct tune.

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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.

Referring to a particularly treacherous section of South
Korea's singing highway, Seung-Hwan Shin, manager of the Korean Highway
Corp., said, "That place is in a downhill, S-curved road, so there's
been lots of accidents from dozing and speeding."

Shin, along with other Korean highway officials, hope these new
roads significantly reduce the number of accidents caused by distracted
drivers every year.

But creating these singing streets isn't easy. It takes
thousands of grooves carved into a road to create even one song. Shin
said construction for one song took four days. On Korean highways, the
song of the streets is the simple, yet sweet "Mary Had a Little Lamb."

Transforming those vibrations into a melody, however, depends
on the distance between the grooves, which may vary between 5.3
centimeters and 10.6 centimeters. The rhythm, on the other hand, is
controlled by the length of the groove. For example, to get one second
of the C, or "do" note, the groove must be stretched to 28 meters.

But the makers of the iPod have little to worry about this new
competitor. The optimal speed for listening to these songs from the
road is a safe 62 mph. At faster speeds, motorists still hear the
music, but instead of an easy-listening song, they hear the annoying
Alvin and the Chipmunks version, and slower speeds have a slow-mo
effect on the song, making it virtually impossible to decipher.

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The
idea behind the singing highways is a good one, and officials hope that
version 2.0 of this new technology will have all the kinks worked out.

[Guest srobak]

Neat, but I guess the engineers didn't think about how much damage is done to tires that are exposed to those over prolonged periods of time. And I bet the motorcycle crowd has to be calling for the government's heads! The one guy mentions they put them on a downhill S-curve somewhere - would love to see how that works out in the rain or snow... less contact patch = bad.

[Islander]

Motorcycles usually have more difficulty with longitudinal grooves, like those rain grooves on California highways. I don't know if they're still in use, but they made real trouble for some bikes and riders and maybe even caused some tires to be redesigned. The grooves on that Korean highway are transverse and would just be felt as a bumpy surface.

"Less contact patch = bad." Not so sure about that. A slick tire has the maximum contact patch the tire profile can provide, but they're not so good in the rain and snow. Those transverse grooves should improve drainage and cut down on hydroplaning for all vehicles.

I'd agree that the grooves might increase tire wear, but it seemed that they were only used in certain sections, not on all of the highway. The possible reduction in crashes would likely offset any tire wear increases. Time will tell.

[WMcD]

For what it is worth.

My high school physics teacher in the early 1970s told me about a similar project.

Reportedly, the message was encoded in the pavement and was placed in the path before toll booths or turns. It would say. "Slow down, slow down, slow down."

As with playing a record on a turntable: If the vehicle hit this patch at a high speed, the message was high pitched and urgent. SLOW-DOWN-SLOW-DOWN-SLOW-DOWN. Then at low speeds it was s-l-o-w d--o-w-n.

Per the teacher, this project was not put into place because drivers encountering it in test situations got into a panic over the road talking to them. It seems farfetched, but such is the tale.

I also wonder whether this really was done back in those days. Making some sort of acoustic mold to form concrete would be a massive technilogical undertaking.

A good story though.

Gil

[Guest srobak]

Islander - I have 18,000 miles on bikes this year - riding over transversely notched out sections of road like this (think rumble strips) is NOT fun. I do agree about the longitudinal grooves also... bridge grates and whatnot. Have ridden with a few people this year who get all panic struck about them... and they think I am nuts when I tell them to loosen up their grip and not fight the bike. Let it flow and worry about balance. Then they do it, and are usually amazed