Different roundabout design, more choices

Published 10:25 am Thursday, October 2, 2008

Plans for a teardrop shaped roundabout, scheduled for construction at the intersection of Interstate 90 and state Route 202, has been dropped. In its place, a circular roundabout with more options is the new plan, said Washington Department of Transportation (WSDOT) officials during a North Bend City Council meeting last week.

During the meeting, WSDOT Project Engineer Dave Edwards unveiled the new design and said the circular roundabout is identical to two others already installed in Monroe and in Waterville.

“The roundabout will increase safety, reduce delays and reduce backups onto the I-90 freeway,” Edwards told the council.

In an e-mail, City of North Bend Public Works Director Ron Garrow said, ” The teardrop configuration works well in conjunction with another teardrop at the other off/on ramps. Without the second teardrop, there is no way for a north-bound driver on state Route 202 to do a U-turn.”

About 30 people attended the last public meeting, held in October, where WSDOT officials held an open house and displayed the original design, which was a teardrop shaped roundabout.

At that time, WSDOT officials collected public comments and studied these to consider changes.

After reviewing all the comments, WSDOT officials decided they should make a design change to the roundabout and add some aesthetic changes to the landscape design, as well. The teardrop design would be dropped and a circular roundabout would be built instead. Native plants and schrubs that survive with minimal maintenance would be placed about the intersection.

Garrow agreed with the design changes for the roundabout because he has driven through an identical design and saw first hand how effective it controls traffic.

In an e-mail, Garrow said: “There is an interchange like that in Arcata, Calif. on Highway 101. I saw it last year when I passed through there. It works very well.”

Edwards showed a computer animated simulation of how the traffic would flow onto and off of I-90, exit 31. It also demonstrated how traffic would flow from the roundabout onto Ribary Way and North Bend Way.

But some council members had lingering concerns about traffic backups and the aesthetics of the roundabout.

Council member Jonathan Rosen didn’t think the simulation was the same as the design.

“What about off-ramp backups? The off ramp traffic could back up going from I-90 to state Route 202,” Rosen said.

Edwards assured Rosen that the simulation included values such as distance and traffic growth for the next 20 years.

Edwards pointed to other advantages.

“In the winter, storms will not stop roundabout traffic like a power outage stopping intersection traffic,” he said.

The project will be advertised for bid January 2007. Construction will begin April 2007 and the roundabout will be open to traffic by September 2007.

“Construction will take about six months,” Edwards said.

The construction portion of the project is funded by the 2003 Gas Tax or “Nickel Tax” the remaining funds come from the general budget.

During construction, Edwards said there will be one side of the roundabout open to move one-lane traffic intermittently in both directions. Once one side is complete, the other side will be closed to one-lane traffic.

Edwards said he and city staff will work together on the landscaping and overall finished look of the roundabout and that the project budget would allow for some changes and choices to meet the city’s preferences.