Plans for two projects that could bring roundabouts to busy intersections in Forest Grove are advancing, according to project managers.
One project that would include that construction of a roundabout where Northwest Martin Road intersects Quince Street, signed as Highway 47, is about halfway through the design stage, according to Renus Kelfkens, project manager with the Washington County Department of Land Use & Transportation.
The project will involve replacing a bridge over Council Creek. In December, the county had to do an emergency fix to failing culverts under the bridge.
Kelfkens expects construction to begin on the project in spring 2021.
Additionally, an analysis of another problematic intersection — the junction of Highway 47, Maple Street and Fern Hill Road, on the south side of Forest Grove — has determined that a roundabout would best alleviate traffic and safety issues there, according to Kelfkens.
"The roundabout was slightly preferable," Kelfkens said.
However, he added, there are potential complications. Most notably, there is a rail crossing on Fern Hill Road just south of the highway, which could affect the traffic flow on a roundabout.
Traffic has long been unpredictable and created safety hazards at the intersection because three different types of roadway converge there.
Highway 47, also known on that stretch as Southwest Tualatin Valley Highway, is a state highway that runs from McMinnville to Clatskanie. It's a major commercial route that passes through cities — including Forest Grove and Banks — as well as farmland and timberland, carrying log truck traffic, combines and more.
Maple Street is a residential street in between Highway 47 in the south and Highway 8, also signed as Pacific Avenue, in the north.
Fern Hill Road is a county road that runs from Forest Grove south toward Gaston. The Forest Grove School District has offices and a bus barn off Fern Hill Road just south of the Highway 47 intersection. Across the road, Clean Water Services operates the Fernhill Wetlands natural area. Further south, there's a water treatment plant run by the Joint Water Commission. The road is also used by commuters as a connection to Highway 219, or Southwest Hillsboro Highway, via Southwest Blooming Fern Hill Road.
Constructing a roundabout would increase safety by slowing traffic and allowing vehicles to make turns more fluidly, Kelfkens said.
"When it comes to the crash data, that was shown to be the most favorable," he said. "That's what really set it ahead."
He added that the maintenance costs of roundabouts are lower than those of traffic signals, another option that was considered.
But there's still a lot that has to be worked out with the project, Kelfkens said.
The Oregon Department of Transportation hasn't yet provided comments on the intersection analysis. The agency's comments will likely be influenced by how an active rail line running adjacent to Highway 47, immediately south of the intersection, would affect the roundabout, Kelfkens said.
For roundabouts to function properly, traffic has to be able to flow continuously. The flow of southbound traffic from the roundabout onto Fern Hill Road would shut down when railroad crossing arms come down for a train. School buses also are required by law to stop at railroad crossings, whether there is a train approaching or not.
"How it would all play out is still yet to be determined," Kelfkens said.
The benefit of a signalized intersection would be that the lights could stop traffic until a train has passed, Kelfkens said.
Once ODOT provides comments on the intersection analysis, if a roundabout is still the preferred option, project managers will need to talk to Portland & Western, which operates the rail line, about how to proceed.
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