WEBVTT
Kind: captions
Language: en

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If you drive down a certain stretch of highway
in the California desert, you will hear music.

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It's supposed to sound a little bit like this:

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[William Tell Overture, by Rossini]

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but instead, it sounds like this.

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[William Tell Overture, by Rossini,
but badly out of tune]

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That was the musical road
of Lancaster, California.

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And as you may have heard,
it's a little bit out of tune.

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A lot of money was spent on that road.

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It was a publicity stunt for a car company
who wanted to show off how clever they are.

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And doing the calculations for
something like that isn't really difficult.

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A musical note is a vibration in the air at
a particular frequency.

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And those vibrations can be made by
a violin string or synthesised by a computer

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or - in this case - made by vehicle tyres
hitting grooves in the road.

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The closer the grooves are,
the faster the vibrations, and the higher the note.

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So take the speed limit,

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divide by the frequency of the note you want,

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and that's how often there should be a groove
in the road.

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And if people travel at the wrong speed, well,
it shouldn't really matter.

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It'll just be like slowing down or speeding up
any other piece of music:

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it'll be in the wrong key, but it'll still
sound right to most people's ears.

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It won't sound like that mess.

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So what went wrong?

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At this point, I am indebted to David Simmons-Duffin,

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an assistant professor of physics at Caltech,

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whose interests include Quantum Field Theories
and playing baroque violin.

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Because he was, as far as I can tell,

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the very first person to figure out
what went wrong:

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and the problem was probably the English language.

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Whoever did the calculations said that the
grooves should be so far apart.

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Let's say, four inches for the first note.

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And they meant there should be
a groove every four inches.

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But whoever gave the instructions
to the work crew

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said that the grooves should be
"four inches apart".

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And that was interpreted as four inches between
the end of one groove

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and the start of the next one.

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They didn't include
the width of the groove itself.

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But your ears definitely do include it.

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The highest note on that section of
the William Tell Overture

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should be one octave higher than the lowest.

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That means the frequency should be doubled,

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and that the grooves should be
half the distance apart.

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And they are: if you don't include
the width of the groove itself.

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That error means that every note is distorted
not by a fraction of its value,

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like if you're travelling at the wrong speed,

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but by a constant amount: by the width of
the grooves.

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The higher the note, the greater the effect
of that distortion.

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And the result is the mess that you are about
to hear for a second time.

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And the really strange part?

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This is the second musical road
built in Lancaster, California.

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The first one, built by the car company, was
too close to residents,

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who complained about the constant noise.

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And probably this note here.

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So the city paved over it and rebuilt it...

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to the exact, same, wrong blueprints.

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That's a take.

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That is a take.

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Right there.

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And in order to celebrate that take, I am
going to put my foot down.

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This is an SUV.

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It doesn't, er... it doesn't do that.