The Washington Department of Transportation (WSDOT) is conducting major reconstruction of I-405 from Bellevue to Renton, with major closures expected this Father’s Day weekend.

Construction began in the fall 2020 to widen I-405 by adding one lane in each direction and to create a dual express toll system, similar to the one currently in place when traveling from Bellevue to Bothell, according to WSDOT.

“Right now that area basically from I-90 all the way down to Renton (SR) 167 is about one of the worst routes in the region,” said Craig Smiley, construction manager for WSDOT.

According to Smiley, about 190,000 vehicles travel that route on Saturdays, while about 160,000 vehicles take that route on Sundays.

With the addition of new lanes as well as 50 miles of a managed lane system, individuals can expect considerable improvements in the traffic flow. The managed lane system will allow drivers to pay for consistent and reliable trips while supporting rapid transit and carpooling, said Smiley.

As part of the reconstruction process, the Main Street Bridge in Bellevue closed on Monday, June 13, and will be closed continuously for a 150-day period.

“The new bridge will have the same configuration as the existing,” said Sharif Shaklawun, project engineer for WSDOT, who mentioned how there will be two lanes going in each direction on the new bridge.

Additional Main Street Bridge improvements include widening the sidewalk and bike path. Smiley described the current bike and pedestrian lanes as being “functionally nonexistent,” with the current sidewalk on the south side being 4 feet wide, while the north side offers about a 2-foot buffer.

While the bridge is under construction, the north sidewalk will experience an increase to 8 feet wide, while the south side will have a 12-foot-wide path, according. WSDOT expects the lane widenings to be an improved user experience for individuals who travel by walking and wheeling.

“We understand that construction is super impactful,” said Smiley. “We really ask if people can take public transit or carpool, and travel during off peak hours.”

Alternate routes

WSDOT encourages individuals to use alternative routes.

At 10 p.m. June 17, a full highway closure will take place in order to safely demolish the existing bridge. I-405 between Northeast 4th Street and Southeast 8th Street will be closed until 5 a.m. June 20.

Signs with detour routes will be available for drivers, pedestrians and bicyclists, and congestion throughout detour routes should be expected. For the five-month closure period of the Main Street Bridge, commuters can use alternative routes on Northeast 4th Street, Southeast 8th Street and Northeast 8th Street, which will relieve traffic congestion from Northeast 4th Street.

A map of detours commuters can take during the Main Street Bridge demolition. Courtesy of WSDOT.

WSDOT suggests that those who are driving southbound I-405 use the Northeast 4th Street exit and travel south on 112th Avenue Northeast, where they can re-enter the highway at Southeast 8th Street. For those who are traveling northbound, WSDOT suggests using the Southeast 8th Street exit and traveling north on 116th Avenue to re-enter the highway through Northeast 4th Street.

The entirety of the I-405 reconstruction is expected to last until 2024. WSDOT has seen challenges regarding the COVID-19 pandemic and material supply issues, and more recently a concrete strike, which could affect the project in the long-term, Smiley said.

“Right now in the morning I probably send 30-40 minutes sitting in traffic,” said Smiley. “I’m looking forward to having a significantly improved commute when the project opens.”

For additional information on the I-405 project, click here.