MnDOT will be installing new noise-dampening rumble strips at various locations along the North Shore and Minnesota Highway 61 beginning Monday.
Termed "sinusoidal" mumble strips, it refers to their wave shape. The strips are billed as being rounder and quieter to those outside the vehicle — addressing a longtime complaint of the safety measure designed to alert drowsy drivers.
The 26 miles worth of new rumble strips will go in along several sections of highway. Installs this year will include from mileposts 46 to 50 south of Silver Bay, mileposts 77-78 south of Schroeder, mileposts 100-106 south of Grand Marais, and mileposts 117-128 and 129-133 north of Grand Marais.
The rumble strips will be installed exclusively along the shoulders of Highway 61, and not on the centerline, said the Minnesota Department of Transportation in its announcement on Friday.
Along with scheduled road construction projects, more sinusoidal rumble strips will be installed along Highway 61 over the next few years. The current project cost $99,300, MnDOT told the News Tribune.
"Installing rumble strips along Minnesota highways has been in practice for nearly two decades," MnDOT said in its announcement. "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 rumble strips to be highly effective, MnDOT said. Since the implementation of rumble strips and a wide variety of other of its Toward Zero Deaths measures, Minnesota has seen a decrease in fatalities from 625 in 2000, to 358 in 2017. Serious injury statistics have decreased as well. MnDOT statistics show that 60 people are killed and 600 injured every year in head-on collisions — the sort of crash rumble strips are employed to avert.
MnDOT cited 25 deaths on Highway 61 from 1986-2011 between Two Harbors and the Canadian border in making its case for bringing the safety strips to the scenic roadway along Lake Superior.
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 centerline. They were also noisy to someone outside the vehicle, and depending on the lay of the land, the noise traveled externally.
Since then, MnDOT has improved the design of rumble strips and now utilizes sinusoidal rumble strips — dubbed "mumble strips" — in many locations throughout the state. The new rumble strips still make noise and vibration to alert the driver, but are less audible outside the vehicle.
Traditional rumble strips were rectangular in shape. Sinusoidal rumble strips are rounded in shape, changing the noise when driven over, MnDOT said.
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