BOULDER COUNTY, Colo. — Most of the sounds in Boulder Canyon flow sweet and peacefully though the trees, but a new sound just moved in that one resident says can overpower even the loudest growl from a mountain lion.
“Rumble strips,” said Boulder Canyon resident Gary Behm. “The sound is awful, Brrrrrruup! Brrrrrruup!”
The sound created from a vehicle rolling over a rumble strip is unmistakable, inside and outside a car. It’s a very loud, jarring rumble that can shake your vehicle and rattle everything in it when you drift over one. Rumble strips are just deep gouges, cut into the pavement along the center or side of a road. The sound is designed to be startling enough to immediately grab your attention or wake you up if you fall asleep and drift out of your lane or worse, off the road.
Shortly after Highway 119 was repaved late in 2020, the rumble strips were replaced. The original rumble strips were cut into the road as a safety feature back in 1996. Since then, the strips wore down enough not to be noticeable. It only took a few weeks of the new road roar to be the breaking point for Gary so he contacted project managers with CDOT pleading with them to turn down the noise.
“I've lived here for 51 years and about 15-20 years ago, CDOT put in a grooved center line and I heard traffic cross that line maybe a couple of times a day. Now it's two to three times every five minutes. I don't know why there's a difference, but it's there. It's driving me crazy,” Behm said.
Jared Fiel with CDOT region 4 said the strips were put in that area for safety.
“Yes, the noise is bad, but a car into your living room is worse," he said. "We found, especially in the winter when you can’t see the center line, the rumble strip is the best way to know if you cross over into the other lane. It will remind you where you are in the road. The outside noise is not the intent of them, but it is a byproduct of them.”
A CDOT traffic study done after the 1996 rumble strips were installed found head-on collisions were reduced by 34% and side swipe accidents were reduced by almost 36%. The study concluded that centerl ine rumble strips have been an effective way to reduce crashes traveling through the corridor.
There is one mention of noise impacts in the 1996 study when there were very few residents in the canyon: "Another question associated with center line rumble strips was the increase in noise levels but, since the highway is through US Forest Service land for most of its length, noise was not a significant problem. There are very few homes near the highway after the first 2-3 miles and only one complaint was received by CDOT about noise levels. The property owner wrote to say that he felt the rumble strips had a positive effect. While they raised the noise levels, they seemed to make driving in the area safer. Center line rumble strips were received so well by the community that we recommend they be installed on the high volume parts of US 6 and SH 119 near the gaming areas of Central City and Black Hawk."
Before Behm and other nearby residents complained to CDOT, it seemed project managers were content with letting time wear away the noise slowly.
“Over the course of many years, the previous rumble strips had worn off or had been filled in by small maintenance overlays,” said Maisie Wingerter, public information official for Kiewit Infrastructure, the group constructing the road improvements in an email to Behm. “Please understand that these are fresh-cut rumble strips with sharp edges so they will produce more noise for a while. After some period of time, the edges will smooth with traffic and plows and sand and become less noisy.”
Wanting more immediate relief, Behm would not back down. He continued his email campaign vowing to go all the way to the top. After a final meeting CDOT realized they could turn down the rumble to a mumble while still offering driver safety.
“When we heard people complaining about the noise and asking what we could do to make it better, we met with the residents and came up with a compromise where we will mill the rumble strip down by about 1/3 with the understanding that it will mitigate the sound outside the car but you will still hear the sound inside a car if you cross over the center line,” said Fiel.
“Yes, the compromise is great news,” Behm said. “This is an acceptable outcome, as I was only hoping for the warning signs to be put back up. The reduction in rumble strip size is a surprising plus.”
As part of the compromise with residents, CDOT also agreed to put back warning signs that let drivers know the rumble strips are there. The original center line rumble strips installed onHighway 119 west of Boulder were the first in Colorado. Back then, since Colorado drivers didn’t have any experience with them, CDOT had concerns that drivers should be made aware of the new installation. CDOT was particularly concerned for motorcyclists and bicyclists due to potential loss of control when riding over them.
These were the primary reasons for installing the original “GROOVED CENTER LINE” warning signs. Since then, research has shown that the effects of center line rumble strips on motorcycle stability are not substantial so they were taken down. Even so, Gary welcomes the return of the warning signs.
“It’d be at least a warning to let them know the strips are in the center line and if you cross them you will be rumbling,” Behm said. “It might help reduce the number of crossovers and that would be less noise.”
“We’re at the very high point of what the volume will be,” Fiel said. “Obviously they will wear down over time, they will fill up with debris overtime so we know that this is the loudest it will be and we’re gonna keep trying to keep mitigating that as much as we can.”
CDOT says the grinding down of the grooves and the replacement of the warning signs will come this spring when much of the 2013 flood repair work in the canyon is complete.
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