Why does it only work "when cars are traveling at exactly 45 mph"? Wouldn't any constant speed work? You would simply play the song in a different key depending on the speed, like changing the speed of a record player.

There are many variables that do not vary linearly with the speed (e.g. rubber's stiffness) so it could be that the sound is indistinguishable at higher speed.

The goal is clearly to slow people down, so that would be really surprising if it would work the same way at higher speed, wouldn't it be? Maybe I'm just too naive..

Yeah but at most speeds, it would probably sound like an out-of-tune instrument

There's a J G Ballard short story where roads of the future are sponsored by tire companies and if you don't have the right tires, you get an awful, noisy resonance through your vehicle. So you have to buy the tires du jour. But then another company gets the sponsorship, and so on..

If I drive at 90 mph, I'll still hear the song, but up an octave, correct?

You can also hear a secret message if you go over it in the opposite direction.

"Tuurnn arround"

"Wrong Way"

Sometimes I see people drive the wrong way down one-way streets, maybe this would help.

Yes, at double the tempo.

This reminds me of a main street somewhere in France that rewards good drivers by giving them a non-stop flow of green lights if they drive at exactly the speed limit.

Speeding down that street is pointless, because you are guaranteed to hit a red light if you do.

San Francisco has a few of these, but they're keyed to bicycle speeds (13 mph or so).

On the other hand, there was an article here about something Portugal did about speeding. Basically, they would put a useless stoplight in the middle of nowhere. Normally it's green all the time, since it's not actually an intersection. If you approach it while speeding, however, it turns red.

A number are keyed to car speeds (eg westbound on Fell from Octavia to Stanyan and on Oak in the other direction).

They end up causing me so much frustration when someone is going just below the speed needed and I can see the lights changing sooner... and sooner... until I miss it.

Haha, which streets? I'm a bike messenger here in SF and haven't noticed any streets that are noticeably bike-paced. I have noticed car-paced series of lights like fell/oak/masonic in the haight where you have to book it at 30-40mph to make it through efficiently.

Edit: now that i'm thinking about it, a lot of the streets in the TL, fidi, and soma are pretty well timed for bikes, but for a faster pace, like 20 or so, and maybe 25-30 for the big soma streets like folsom, howard, harrison, bryant.

Valencia (between 14th and 26th) is timed at 13mph northbound in the morning, and southbound in the evening.

Oh, you're totally right. I don't work in the mission that often, so i forgot about that.

Great Highway in SF is timed to exactly 35mph IIRC.

That would never fly in America - we would prefer a method that generates revenue for the police.

Couldn't people just run the red, especially if there's no intersection?

Sounds like a perfect job for a red light camera though.

We do. Especially at night.

Normally those red lights are placed around schools and such.

If you're a responsible driver, you're already driving at the speed limit at those sites.

There are many streets in New York that are like this, experienced cab drivers know this and will take routes that take advantage of "cascading lights".

In fact the fastest/cheapest route to prospect heights from lower manhattan is to take the williamsburg bridge to lee ave, to nostrand ave, where you can catch a long stretch of cascading lights.

I saw that in a small town in Middle America when I was a kid. They had a grid system, and they had the lights synced to 25 MPH. They didn't even post a speed limit - just a statement that the lights were synced. Once you realized that they were telling the truth, you drove 25 MPH. Why would you do anything else?

Most of the world does this, it's standard traffic engineering.

The French term for this is "onde verte" ("green wave"), and from memory it is/was mentioned somewhere in the French traffic code. Here is a reference (in French) https://fr.wikipedia.org/wiki/Carrefour_%C3%A0_feux#Coordina.... That said, as far as I know that this is specific to France at all.

Only works at exactly 45 mph?

How dumb/gullible do you think your readers are, Smithsonian Mag?

This is a minor plot point in "The Big Over Easy" by Jasper Fforde [0], which features a road that plays Jerusalem if you drive along the rumble strips at precisely twenty-nine miles per hour. Personally, I prefer the Stockhausen symphonies of the potholes on the M25.

[0] http://www.amazon.com/Big-Over-Easy-Nursery-Crime/dp/0143037...

I was hoping for something a little more OK Go than this... Pity there's no real substance to the article, it would be interesting to see how speed alters the tune, I'm assuming that changing speed doesn't have a linear relationship, otherwise as said elsewhere, 90mph would mean an octave up and twice the tempo.

Multiply the speed by the 12th root of 2 (1.059...) to transpose up a semitone. Repeat for further semitones.

When you get to the 12/12 root of 2 you get a factor of 2, which gives you 12 semitones up at double the speed.

I have a strong suspicion that is exactly what would happen.

Drivers will drive 50,60,90 because playing it faster doesn't make it sound worse, and since it already sounds awful, due to bad acoustics, drivers will want to be off it ASAP

That would be terrifying at night if you weren't aware of it and say you were a tourist lost and scared then your car starts making music.

There is one in Lancaster, CA if you ever find yourself there. It was originally built for a Honda commercial but was moved a few miles out of town after nearby residents complained.

[1] http://www.wsj.com/articles/SB122469915344259035

I prefer the tune at 90bpm as opposed to 45bpm.

Fun idea, but yea it seems like this could encourage some people to drive faster just to hear what it sounds like sped up.

At least it'll discourage people from crawling at 45mph in a highway.

I'd hardly call it desolate, it's about 2 miles from the edge of Albuquerque and pretty busy most times.

Neat, though.

If you speed, you will be forced to hear Justin Bieber at full blast.

That'll cut down speeding in no time.

They don't mention why America the Beautiful was selected. I don't know that particular song, but Route 66 would surely have been preferable. A classic.

Could it be that RIAA would have been wanting to collect royalties on every "performance"?

From the video: "I'm tempted to go 80 miles-per-hour to see what it sounds like... But I probably won't".

You know he totally did. Just saying that probably created an irresistible urge, he might have even done it immediately afterwards.

I experienced the musical highway (a segment of Route 66) last year while on a trip around the Four Corners area and enjoyed its rendition of "America The Beautiful". It was amusing and, sadly, short.

That's cool but I still think it's just finding yet another way not to implement the actual solution for speeding - ANPRs powering automated ticketing and something like "three strikes and then your license get suspended". As long as drivers can easily get away with irresponsible road behaviour, they will be speeding.

I'm always amazed that they have speed cameras in Europe/Australia but not here. It seems like such a no-brainer for cities that have already landed on the "limited privacy" side of the spectrum and have things like red light cameras and license plate collectors.