This California Highway Sounds Horrible Because of Bad Math

Who knew a road could be out of tune?

If you're going to build a musical highway, the finale of the William Tell Overture isn't a bad choice. Who doesn't want to hear this as their car gallops along? Just make sure you don't build the song out of tune.

In a new video, YouTuber Tom Scott drives across a stretch of road in Lancaster, Calif. that's supposed to play the famous classical piece via the sound of tires hitting grooves in the road. But the song is way out of tune and barely recognizable, and that's because of a common but simple mistake by the crew that built this.

As Scott explains, it's a relatively simple matter to calculate how far apart to build the road grooves to generate the note you want. The mistake by the road crew was not accounting for the width of the grooves themselves.

It's an important consideration. Say you're cutting wood with a circular saw and the blade is 1/8" thick. If you cut right down the middle of your pencil mark, you'll shave off 1/16th of an inch on either side of the measurement and your board won't be quite perfect. In the case of the road grooves, you've got to know whether the measurement for groove frequency is taken from the middle point of one groove to the middle point of the next, or from the ending of one groove to the beginning of another. Get it wrong and, well, just listen to Scott's video.

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