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Roundabout

ODOT studies show roundabouts reduce injury accidents by 75 percent

The Oregon Department of Transportation has begun initial work to install a roundabout at Clow Corner and 99W.

The Oregon Department of Transportation has begun initial work to install a roundabout at Clow Corner and 99W. Photo by Jolene Guzman.

POLK COUNTY — Studies nationwide show that modern roundabouts reduce fatal crashes by 90 percent.

They reduce injury accidents by 75 percent.

Those statistics, courtesy of the Federal Highway Administration and Insurance Institute for Highway Safety, are just two of the reasons the Oregon Department of Transportation has lobbied for a roundabout at the intersection of Clow Corner Road and Highway 99W.

Until recently, local officials have advocated for a traffic light at the intersection, citing the success of the Hoffman Road and 99W traffic light installed about 15 years ago. There have been no fatalities at the intersection, and the number of crashes has declined by 71 percent, according to county officials.

The Polk County Board of Commissioners voted, with some reservations, to work with ODOT on installing a roundabout at Clow Corner, the site of a fatal accident in September. All three commissioners said they felt a light — the less expensive option at about $1.2 million compared to about $5 million for a roundabout — would be effective there, but wanted to move on making the intersection safer.

Tim Potter, ODOT’s Area 3 manager, said an evaluation performed in 2016 had the intersection failing “warrants” for a signal. The study evaluated a set criteria, or warrants, including traffic volumes over and an eight- or four- hour period, peak hour traffic, pedestrian usage, and how close the intersection is to a school or rail crossing.

“Franky Clow Corner didn’t meet any of those warrants,” Potter said. “That immediately sets an uphill challenge (for a light).”

He added that while they are close together, Hoffman and Clow Corner are not identically situated. Hoffman is closer to an urban area in Monmouth, Potter said. Drivers traveling north on the highway just left an urban area and wouldn’t be surprised to encounter another signal, he said.

However, the same evaluation was done in 2007, and Clow Corner passed the warrants test. At the time, the analysis was conducted as part of an overall highway corridor study and didn’t have funding attached.

When money was placed in an account for a safety upgrade in 2013, ODOT had begun looking at other solutions, including a roundabout and redesigning the intersection to improve safety.

“We were looking for a solution that we felt would overall solve the problem better than a signal could,” said Angela Kargel, ODOT’s Region 2 traffic manager.

Kargel said she didn’t think the success of the light at Hoffman Road would be repeated at Clow Corner.

“It doesn’t solve the problem,” she said. “It most likely will not solve the problem.”

Todd Whitaker, Polk County’s public works director, said the Hoffman signal has outperformed the averages.

“Right now, we’ve seen a 71 to 73 percent reduction in serious and fatal accidents at Hoffman Road, but that is better performance than they see nationwide,” he said. “Generally, they see 40 to 50 percent crash reduction.”

Whitaker said he didn’t agree with all of the engineer’s conclusions in the 2016 warrants analysis, but agreed it would be a difficult sell to continue to ask for a signal.

Potter said roundabouts greatly reduce the chance of high-speed rear-end accidents and eliminate the possibility of red-light running accidents, which can be severe. He said the one-way traffic flow of roundabouts reduce the number of “conflict points” — where cars can collide — to just one, so drivers don’t have to time the movements of multiple vehicles.

“The decision points are less,” he said.

Nationwide, roundabouts experience a 37 percent reduction in accidents overall, and when they do occur they are less severe, Potter said.

“That crash is generally a side-swiping kind of crash, more of a glancing blow,” he said.

Design elements, such as a curve in the road leading to the roundabout will slow traffic, another safety measure.

ODOT and county officials still have significant tasks ahead of them.

ODOT has designated $3.39 million for Clow Corner, not enough to finish the project. Potter said since establishing the partnership with the BOC last month, he’s taken the request to his higher ups and has gotten support. He believes the funding will be found and preliminary work is underway.

He said he is fairly confident the work could be done between three and four years.

The next challenge will be design. Potter said ODOT learned lessons from a roundabout recently installed on Highway 42 and Verboort Road, an intersection similar to Clow Corner in traffic volumes and the type of freight using it.

He said ODOT will enlist the help of freight companies and local farmers who move their equipment through the intersection.

“We are all in this together, with the goal to improve safety and still have a functional highway,” he said.

Another part of the plan is driver education, Potter said. Drivers in this area are not familiar with highway roundabouts and it will take some adjustment and an education campaign before the intersection opens.

“Rural roundabouts, they are new in Oregon,” Kargel said. “They are not new in a lot of other places. It’s a learning curve for everybody.”

“The decision points are less,” he said.

Nationwide, roundabouts experience a 37 percent reduction in accidents overall, and when they do occur they are less severe, Potter said.

“That crash is generally a side-swiping kind of crash, more of a glancing blow,” he said.

Design elements, such as a curve in the road leading to the roundabout, will slow traffic, another safety measure.

ODOT and county officials still have significant tasks ahead of them.

ODOT has designated $3.39 million for Clow Corner, not enough to finish the project. Potter said since establishing the partnership with the BOC last month, he’s taken the request to his supervisors and has gotten support. He believes the money will be found, and preliminary work is underway.

He said he is fairly confident the work could be done between three and four years.

The next challenge will be design. Potter said ODOT learned lessons from a roundabout recently installed on Highway 42 and Verboort Road, an intersection similar to Clow Corner in traffic volumes and the type of freight using it.

He said ODOT will enlist the help of freight companies and local farmers who move their equipment through the intersection.

“We are all in this together, with the goal to improve safety and still have a functional highway,” he said.

Another part of the plan is driver education, Potter said. Drivers in this area are not familiar with highway roundabouts, and it will take some adjustment and an education campaign before the intersection opens.

“Rural roundabouts, they are new in Oregon,” Kargel said. “They are not new in a lot of other places. It’s a learning curve for everybody.”

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