The Minnesota Department of Transportation plans to install rumble strips along parts of State Highway 61 in Lake County this summer.

Representatives from the MnDOT visited the Lake County Board of Commissioners on Tuesday, April 9, to update the board on various districtwide construction projects.

It is MnDOT's policy to install rumble strips along highways paved with shoulders 4 feet wide or greater and with speed limits of 55 miles per hour or greater to increase safety by preventing run-off road crashes.

A gap will be filled in along the northbound lane of the Two Harbors Expressway from Knife River to the edge of Two Harbors. Another stretch of 4 miles on Two Harbors Expressway just south of Knife River will have rumble strips installed as well.

"We've got wide shoulders there - I think either 10- to 12-foot shoulders," MnDOT planning director Bryan Anderson said. "So we're going with the rectangular rumble strips there, not the sinusoidal."

Sections of Highway 61 have sinusoidal rumble strips - or "mumble strips" - to reduce noise than traditional rectangular rumble strips. These strips were installed due to several complaints the board received from constituents about the sound traditional rumble strips made in the past.

The rumble strips set to be installed this summer are only being applied to the edges of the road, not the center lines, which is what the previous complaints mainly addressed.

"If the mumble strips are so much quieter, why not do them all like that?" Commissioner Rick Goutermont asked.

"On wider shoulders we like to make sure we're really waking up the driver or getting their attention. Sinusoidal, especially in the winter months, they can get filled up. The rectangular ones still give a bigger bang for the buck," Anderson said. "That said, when we have narrower shoulders, we do go with the sinusoidal along the edges of the road. These traditional ones will be placed farther back from the immediate edge."

Installation is expected to begin in mid-August and last through mid-September.