8/14/2007
Rumble strips help motorists avoid rumbling off the road or crossing into oncoming traffic
BOISE - 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're crossing into the opposite lane, or getting close to veering off the side of the road.
The Idaho Transportation Department is installing rumble strips on the double yellow center line of highways to help motorists stay the course. Previously, the rumble strips were installed only on highway shoulders about a foot outside of the white fog line.
The strips are raised or grooved patterns placed primarily along paved shoulders. When tires pass over them, they produce a sudden rumbling and vibration throughout vehicles. The sound and vibration alert fatigued or distracted drivers that they're beginning to drift.
"We are installing more than 300 lane miles of rumble strips across Idaho this summer," Kimbol Allen, a transportation department engineer, said. "We are placing them on Idaho 21, Idaho 55, Interstate 90, I-84, Idaho 3, U.S. 12 and U.S. 95, among other routes."
That number includes 100 miles of center line rumble strips in no-passing zones.
"We are trying to discourage people from crossing that double yellow line," Allen said. "It's a reminder that it's not safe to pass."
That reminder will help motorists on U.S. 12. The center line rumble strips were installed between milepost 111 and milepost 147.78 in June. John Dickeson, a transportation department project manager in Lewiston, said the strips will help truck drivers safely navigate this portion of U.S. 12.
The route winds along the Clearwater River and in many places is confined by steep slopes on one side and by the river on the other, leaving little or no room to add shoulder rumble strips. The center line rumble strips placed at U.S. 12 no-passing curves are designed to reduce head-on and side-swipe crashes.
"A lot of truck traffic was crossing the center line. The rumble strips alert the driver they are drifting onto the wrong side of the road," Dickeson said. "It's a good and inexpensive safety improvement."
A three-year safety study showed there were 213 vehicle crashes on a segment of U.S. 12, with 71 percent of those crashes involving single vehicles. Center line rumble strips might have prevented more than 14 percent of the 213 crashes had the strips been in place.
The study also showed that 21 percent of the 62 multiple-vehicle crashes were side-swipes involving vehicles traveling opposite directions. The side-swipe usually occurred when one of the vehicles crossed the center line.
The fog line rumble strips also are designed to help motorists stay in their lane. Approximately one-third of all traffic fatalities and serious injuries in the United States each year are due to run-off-road crashes. In 2000, almost 16,000 deaths were attributed to those types of accidents.
On Interstate 15, Interstate 86 and U.S. 91 in eastern Idaho, there has been a decrease in accidents attributed to drowsy or fatigued driving. After rumble strips were installed, there was an 11 percent decrease in crashes with fatigued drivers behind the wheel.
I-15 is a long freeway with a history of run-off-road type crashes. From 1995 to 1998, 1,979 crashes occurred on the 196 miles of I-15 in Idaho. Of these, 1,539, or 78 percent, were single vehicle crashes. Rumble strips have been installed on all four shoulders of I-15, about six inches to the right or left from striped shoulder borders.
In their first year of installation, the Idaho State Police said single vehicle off-the-road rollover crashes were reduced by 50 percent on I-15.
The rumble strips also benefit patrol troopers and maintenance/construction crews, both of whom are frequently standing on highway shoulders.
"Our troopers and ITD workers, while they're out on the roads, now have a little bit of heads-up," said Idaho State Police Cpt. Ed Gygli in eastern Idaho. "They'll be out on a traffic stop or project, and they'll hear those rumble strips go off. It gives them a little more time to react. It's an early warning system for those of us who work out on the roads."
Those benefits and the reduction in accidents have prompted the transportation community in recent years to use rumble strips more, rather than relying on clear roadsides and traffic barriers to minimize crash severities.
"Our primary goal is to reduce single-vehicle crashes and fatalities, and rumble strips have proven to be a cost-effective way to keep motorists on the roadway," Allen said.
That slight shuddering you feel, and hear, as you're driving is a warning you're crossing into the opposite lane, or getting close to veering off the side of the road.
The Idaho Transportation Department is installing rumble strips on the double yellow center line of highways to help motorists stay the course. Previously, the rumble strips were installed only on highway shoulders about a foot outside of the white fog line.
The strips are raised or grooved patterns placed primarily along paved shoulders. When tires pass over them, they produce a sudden rumbling and vibration throughout vehicles. The sound and vibration alert fatigued or distracted drivers that they're beginning to drift.
"We are installing more than 300 lane miles of rumble strips across Idaho this summer," Kimbol Allen, a transportation department engineer, said. "We are placing them on Idaho 21, Idaho 55, Interstate 90, I-84, Idaho 3, U.S. 12 and U.S. 95, among other routes."
That number includes 100 miles of center line rumble strips in no-passing zones.
"We are trying to discourage people from crossing that double yellow line," Allen said. "It's a reminder that it's not safe to pass."
That reminder will help motorists on U.S. 12. The center line rumble strips were installed between milepost 111 and milepost 147.78 in June. John Dickeson, a transportation department project manager in Lewiston, said the strips will help truck drivers safely navigate this portion of U.S. 12.
The route winds along the Clearwater River and in many places is confined by steep slopes on one side and by the river on the other, leaving little or no room to add shoulder rumble strips. The center line rumble strips placed at U.S. 12 no-passing curves are designed to reduce head-on and side-swipe crashes.
"A lot of truck traffic was crossing the center line. The rumble strips alert the driver they are drifting onto the wrong side of the road," Dickeson said. "It's a good and inexpensive safety improvement."
A three-year safety study showed there were 213 vehicle crashes on a segment of U.S. 12, with 71 percent of those crashes involving single vehicles. Center line rumble strips might have prevented more than 14 percent of the 213 crashes had the strips been in place.
The study also showed that 21 percent of the 62 multiple-vehicle crashes were side-swipes involving vehicles traveling opposite directions. The side-swipe usually occurred when one of the vehicles crossed the center line.
The fog line rumble strips also are designed to help motorists stay in their lane. Approximately one-third of all traffic fatalities and serious injuries in the United States each year are due to run-off-road crashes. In 2000, almost 16,000 deaths were attributed to those types of accidents.
On Interstate 15, Interstate 86 and U.S. 91 in eastern Idaho, there has been a decrease in accidents attributed to drowsy or fatigued driving. After rumble strips were installed, there was an 11 percent decrease in crashes with fatigued drivers behind the wheel.
I-15 is a long freeway with a history of run-off-road type crashes. From 1995 to 1998, 1,979 crashes occurred on the 196 miles of I-15 in Idaho. Of these, 1,539, or 78 percent, were single vehicle crashes. Rumble strips have been installed on all four shoulders of I-15, about six inches to the right or left from striped shoulder borders.
In their first year of installation, the Idaho State Police said single vehicle off-the-road rollover crashes were reduced by 50 percent on I-15.
The rumble strips also benefit patrol troopers and maintenance/construction crews, both of whom are frequently standing on highway shoulders.
"Our troopers and ITD workers, while they're out on the roads, now have a little bit of heads-up," said Idaho State Police Cpt. Ed Gygli in eastern Idaho. "They'll be out on a traffic stop or project, and they'll hear those rumble strips go off. It gives them a little more time to react. It's an early warning system for those of us who work out on the roads."
Those benefits and the reduction in accidents have prompted the transportation community in recent years to use rumble strips more, rather than relying on clear roadsides and traffic barriers to minimize crash severities.
"Our primary goal is to reduce single-vehicle crashes and fatalities, and rumble strips have proven to be a cost-effective way to keep motorists on the roadway," Allen said.