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Idaho Transportation
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P.O. Box 7129
Boise, ID 83707
208.334.8005
Fax: 208.334.8563

 


Rumbling warns drivers when they cross the line

There’s nothing wrong with your vehicle’s alignment. And your iPod is working just fine.
That slight shuddering you feel, and hear, as you’re driving is a warning you are crossing into the opposite lane, or getting close to veering off the side of the road.

ITD is installing rumble strips on the double yellow center line of highways and outside of the white fog line to help drivers stay the course.

Rumble strips are raised or grooved patterns constructed primarily along paved shoulders. Tires pass over them, producing a sudden rumbling and vibration in the car. The sound and vibration alert fatigued or distracted drivers that they are beginning to drift.

The strips are created by grinding a series of parallel grooves in the asphalt that are about 12 inches wide and one-half to five-eights of an inch deep. Traditionally, they are used on the outside edges of highways to keep motorists from driving onto soft shoulders where they often over-correct and lose control of their vehicle. Their new centerline use is designed to reduce head-on and side-swipe crashes.

Rumble strips are being added along sections of highways like Idaho 21, a two-lane, popular recreation route from Boise to Idaho City that has numerous curves. They also are prominent on the center line of Idaho 55 segments between Horseshoe Bend and Cascade, another route heavily traveled by recreational traffic.

Kimbol Allen, a transportation department District 4 resident engineer, said the department has awarded at least two contracts to have rumble strips installed.

The most recent rumble strip installation started this year just after Memorial Day, and is scheduled to be finished this week.

“This project cuts in about 300 lane miles of rumble strips in all six districts,” Allen said.

“We’ve got them on I-90, on I-84, Idaho 3, U.S. 12 and U.S. 95, among other routes.”

Published 7-20-07