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The state’s dilemma of safety versus noise

(WSDOT)

To rumble or to mumble? That is the question facing traffic engineers who want to keep you safe but want to keep the roads quiet.

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I believe everyone is familiar with rumble strips. They are the grooves cut into the side or middle of roads to let drivers know they are driving out of the lane.

“It creates a vibration and a sound level inside the vehicle that physically wakes them (drivers) up and alerts them that something’s wrong and they need to do something,” Jim Laughlin with the Washington State Department of Transportation said.

Rumble strips have been proven to prevent cross-over accidents, and they have made our roads safer. They have also made them louder. With more developments moving into rural areas where these strips have been laid-down, people are starting to complain about the noise.

Laughlin said that’s where the mumble strip comes in. It is a quieter version of the rumble strip that is gaining popularity.

“We’ve done some research recently to look at what it takes to both wake the vehicle driver and reduce the exterior sound levels as well,” he said.

The state tested these mumble strips, which are a continuous groove running parallel to the road instead of a series of perpendicular grooves, near Coulee City.

“It was able to achieve an eight-decibel increase in the vehicle cabin over the background noise, and we were able to get a ten to twelve-decibel reduction at 25 feet from the roadway,” Laughlin said.

So it’s loud enough to wake the driver while nearly reducing the exterior noise to neighborhoods by half. Laughlin said the plan is to start using these new mumble strips where they make sense and replacing the old rumble strips as part of regular maintenance.

And if we’re really lucky, the state will do what they did on Route 66 in New Mexico to groove the pavement so it plays a song. Drivers who travel 45 miles an hour on the road hear “America the Beautiful.” A creative way to combat speeding.

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