Answer: New Jersey

If you’re a very cautious driver who only drives well rested and with a fresh cup of coffee in hand, then perhaps you’ve never heard the rumble that gives the rumble strip its name. Even if you’ve never had a firsthand encounter with one, however, be thankful they exist since they’ve most certainly alerted a driver or two around you over the years.

Rumble strips are a textured area composed of horizontal grooves perpendicular to the direction of travel found on the side of highways. The strips are usually created via a roll-in or stamping technique while the concrete or asphalt is still setting, but rumble strips can also be cut in, or bolted down in the form of plastic or ceramic modifications. Regardless of how they get dug into the road or added onto the top of it, all the different versions serve one function: to create a startling tactile and auditory feedback for drivers who drift over the boundary line at the edge of the road.

The strips were first deployed on the Garden State Parkway in New Jersey in 1952, and since then, have been used on highways coast to coast across the United States as well as around the world. In addition to their original use as a “shoulder minder”, if you will, on highways, the rumble strip design pattern has also been incorporated as a safety feature in other settings, such as across the entire lane to serve as a warning of an upcoming stop light, sign, construction zone, wildlife crossing, or other potentially unexpected condition.