Musical roads reward drivers who maintain the posted speed limit by playing a song through tire vibrations.
The concept is simple: grooves cut into the pavement at specific intervals create different musical notes as tires pass over them.
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At the correct speed, the vibrations produce a recognizable tune. Drive too slowly and the melody drags; go too fast and it becomes noise.
Only a handful of these unusual roads exist in the United States.
How Musical Roads Work
Vibrations produce every sound, and pitch depends on vibration frequency. Engineers create a melody by cutting grooves at carefully calculated intervals.
As tires pass over the grooves, vibrations travel through the suspension into the cabin.
The spacing between each groove determines the musical note. For example, an E note requires roughly 330 vibrations per second.
At 45 mph (72 km/h), grooves must be spaced about 2.4 inches (61 mm) apart.
Different notes require different spacing, while longer notes extend the pattern over a greater distance.
Safety Purpose and Notable Examples
Most musical roads are built with safety in mind, encouraging drivers to maintain a consistent speed on rural highways.
One well-known example was on historic Route 66 near Tijeras, New Mexico, installed in 2014.
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It played "America the Beautiful" at exactly 45 mph, but the grooves wore away and restoration was deemed too expensive.
Lancaster, California, opened America's first musical road in 2008, playing the finale of the William Tell Overture.
