road safety feature by means of change in tyre noise
Rumble strip Rumble strips, also known as sleeper lines, alert strips, audible lines, sleepy bumps, wake up calls,[1] growlers, drift lines, and drunk bumps, are a road safety feature to alert inattentive drivers of potential danger, by causing a tactile vibration and audible rumbling transmitted through the wheels into the vehicle interior. A rumble strip is applied along the direction of travel following an edgeline or centerline, to alert drivers when they drift from their lane. Rumble strips may also be installed in a series across the direction of travel, to warn drivers of a stop or slowdown ahead, or of an approaching danger spot.