There may be no more recognizable road in the United States than Route 66, and — save for the actual National Anthem — no more well-known patriotic song than “America the Beautiful.” Naturally, someone eventually thought to combine them into one giant symbol of Americana.

Combining rumble strips and math, engineers determined how the spacing between strips affects the pitch of the sound produced when a tire drives over it.

We’re talking about an idea implemented by the New Mexico Department of Transportation (NMDOT) to spice up a stretch of the historical road. Heading east out of Albuquerque, situated between mile markers four and five, lies a unique musical experience. There’s a stretch of road that plays “America the Beautiful” as you cruise along. Using the technology of rumble strips combined with the power of mathematics, the brilliant engineers at San Bar Construction Corp. determined how the spacing between rumble strips affects the pitch of the sound produced when a tire drives over it. 

“The road works by the simplest bit of science,” explains Matt Kennicott, director of communications for NMDOT. “All of the sounds and music notes that we hear in day-to-day life are just vibrations through the air. For instance, anything that vibrates 330 times in one second will produce an E note — a guitar string, a tuning fork or even a tire. To produce an E note with a car, we had to space the rumble strips such that if driven at 45 mph for one second, the car would hit 330 strips. A bit of math tells us this is 2.4 inches between each rumble strip. After that, it’s a case of breaking down the music into exact chunks of time and applying the same technique to each space depending on what note is needed and for how long.”

Stick to the speed limit

Once the proper spacing was determined, the strips were laid and musical notes were painted on the pavement along the quarter-mile stretch. They also installed signs reminding drivers to stay at the 45 mph speed limit or they won’t be able to hear the song. 

“Route 66 is a very historical roadway and [NMDOT] thought it would be neat to do something like this on such a unique piece of highway,” notes Kennicott. “Albuquerque has several classic car clubs that date back to when Route 66 was in its heyday that like to cruise the roadway, so it seemed like a good fit.”

If you want to experience this phenomenon for yourself, be sure to make Route 66 a part of your next road trip!