Tumwater’s plan to tackle 1 problem intersection? Add 3 roundabouts

Tumwater wants to trade in one problem intersection for three new roundabouts in the hopes of easing traffic along Capitol Boulevard at Trosper Road.

The plan is to put a roundabout at the intersection of Capitol and Trosper, another one at the northbound Interstate 5 ramps on Trosper, and a third one on a new north-south street parallel to Capitol.

The work is set to begin in 2020.

Any intersection can only accommodate a certain amount of traffic, said Jay Eaton, Tumwater’s public works director. To make the Capitol-Trosper intersection “big enough” to accommodate future traffic would have required adding several lanes or a three-lane roundabout.

“Historically that’s what you’ve seen happening — you have more traffic and things have to get bigger to accommodate that. On this one, it was getting too big,” Eaton said.

Instead, officials designed a plan to divert traffic from the intersection by providing an alternate route to northbound I-5, which is where many drivers are headed. Drivers coming from the south would be able to take the new street between Trosper and Lee Street, go around the first roundabout, and access the on-ramp there.

Diverting some of that traffic means traffic through the Capitol-Trosper intersection could be accommodated by a two-lane roundabout.

The plan had to be approved by the state’s Department of Transportation because it impacts I-5. The city received a $6.6 million state grant for the $11.8 million project; the rest of the money would come from the city’s transportation fund.

Eaton said 35 percent to 40 percent of the project budget will go to acquiring rights of way, including buying buildings to tear them down. At Capitol and Trosper, the Sound Credit Union building will have to come down to make room for the roundabout. There also is an apartment complex that will have to come down to make room for the new street.

“It’s a challenging area. Anytime you try to do improvements in an area that’s already built up, it’s a challenge,” Eaton said.

The city’s 2014 Capital Boulevard Corridor Plan, which called for improvements in the area to address traffic and encourage development, highlighted the Trosper intersection as a problem area.

People who work nearby agree the changes are needed.

“That makes me really happy because that intersection is really awful,” said Jude Huston, a shift superior at Starbucks on Capitol, less than a block from the Trosper intersection. She said there are often crashes because of drivers trying to turn left off of and onto Capitol from the coffee shop.

Across the street, Mary Blakely at Thompson’s Furniture agrees the current configuration is bad.

“All these business will be impacted once they start tearing up that intersection,” she said. “But I don’t know how they can’t do it. Something has to change.”

This story was originally published January 14, 2018 at 7:00 AM with the headline "Tumwater’s plan to tackle 1 problem intersection? Add 3 roundabouts."