Minnesota Department of Transportation

511 Travel Info

News Release

Aug. 16, 2019

MnDOT installing sinusoidal rumble strips along Highway 61 beginning Monday

DULUTH, Minn. — MnDOT will be installing sinusoidal rumble strips at various locations along Highway 61 beginning Monday.

The sections of highway where sinusoidal rumble strips will be installed this year include from mile posts 46 to 50 south of Silver Bay, mile posts 77 to 78 south of Schroeder, mile posts 100 to 106 south of Grand Marais, and mile posts 117 to 128 and 129 to 133 north of Grand Marais. All of these sinusoidal rumble strips will be installed along the shoulder of the roadway, not on the centerline.

Along with scheduled road construction projects, more sinusoidal rumble strips will be installed along Highway 61 over the next few years.

Installing rumble strips along Minnesota highways has been in practice for nearly two decades. The purpose is to alert tired or distracted drivers when they are drifting across lines, potentially causing a severe or fatal crash. They are also beneficial during winter months when snow, at times, prevents drivers from seeing the edge of the lane.

Statewide, studies have proven rumble strips and sinusoidal rumble strips to be highly effective. Since the implementation of rumble strips, and other safety measures, Minnesota has seen a decrease in fatalities from 625 in 2000, to less than 358 in 2017. Serious injury statistics have decreased as well.

When MnDOT first began installing rumble strips throughout the state, by design, they were noisy inside the car to alert the driver they were too close to the edge or the center line. They were also noisy to someone outside the vehicle, and depending on the lay of the land, the noise traveled. Since then, MnDOT has improved the design of rumble strips and now utilize sinusoidal rumble strips – dubbed mumble strips – in many locations throughout the state. The sinusoidal rumble strips still make noise and vibration to alert the driver, but are much less audible outside the vehicle.

Traditional rumble strips were rectangle in shape. Sinusoidal rumble strips are more rounded in shape, changing the noise when driven over.

Crews will be installing sinusoidal rumble strips on the shoulders only along Highway 61.

To hear the difference in sound between the traditional rumble strips, sinusoidal rumble strips and no rumble strips, visit our website at mndot.gov/d1 and scroll down to click on the links to videos.

For more information and statistics on rumble strips and sinusoidal rumble strips, please visit safety.fhwa.dot.gov/provencountermeasures.

Watch for signage along Highway 61 for lane closures during installation of the sinusoidal rumble strips, and for real-time traffic and travel information in Minnesota, visit 511mn.org.

Follow MnDOT District 1 on Facebook and Twitter at @MnDOTnortheast.