Date:  Tuesday, December 18, 2007

Contact: Lisa Hodgson, WSDOT Project Engineer, 206.437.7242
Colleen Gants, WSDOT Communications, 206.465.2311

RENTON, WA – Emergency repairs to the Thunder Hills Creek culvert damaged in the December 3 storm are on schedule. Crews have been working around the clock to build a 6,000-foot pipe system to divert stormwater from the creek around I-405.

To protect the safety of crews, WSDOT will limit upcoming closures primarily to daytime hours:

• Crews will close the right, northbound lane of I-405 between SR 167 and SR 169 from 10 a.m. to 7 p.m. each weekday. To help keep traffic moving, the HOV lane will be open to all drivers during this time.
• If work continues throughout the weekend, crews will close the right, northbound lane of I-405 between SR 167 and SR 169 from 7 a.m. to 7 p.m. each day. To help keep traffic moving, the HOV lane will be open to all drivers during this time.
• When the right, northbound lane is open, the HOV-lane restriction will be in effect. Only carpools, vanpools and transit will be allowed to use the HOV lane between 7 p.m. and 10 a.m.

“Although we are limiting nighttime closures for the safety of crews working on these repairs, motorists should still be prepared for an occasional closure during evening hours,” said Lisa Hodgson, WSDOT Project Engineer.

WSDOT traffic engineers expect congestion to continue on I-405 and SR 167 and are asking drivers to take alternate routes, avoid trips, carpool, use transit and travel at less congested times of day. Drivers are also encouraged to check the WSDOT traffic Web page, call 511 and tune in to radio traffic reports before traveling through the area.

“It doesn’t take much to create a huge backup in this area,” said WSDOT Traffic Engineer Martin Dedinsky. “We need drivers to be aware of what they are getting into if they plan to travel this route during the closures.”

The problem on I-405 began December 3, when record-setting rain damaged sections of a 400-foot-long culvert that sits 60 feet underneath I-405. The collapse led to a sinkhole just 12 feet from the southbound shoulder of I-405. Crews stabilized the sinkhole, but the culvert is broken. Engineers say without a functioning culvert to carry water under I-405, another significant storm could lead to more damage and possibly force WSDOT to close all lanes of I-405 for safety.

The solution is a two-step process. The contractor will build a pump and pipe system adjacent to the northbound lanes to divert water from Thunder Hills Creek around I-405 via Talbot Road. To build this 6,000-foot pipe system, crews must close one lane, as there is not enough room to construct the system from the shoulder. The second part of the work will be off the road as crews drive a new culvert under I-405 to replace the collapsed section. Part two could take up to six weeks and may be very noisy.

To help keep traffic moving, WSDOT is working around the clock to give drivers as much information as possible. We are:

• Working with local television and radio stations to deliver up-to-date, real time traffic information
• Placing portable signs along the roadway letting drivers know the HOV lane is open to all traffic.
• Using the overhead electronic signs and the 511 system to deliver traffic information to drivers.
• Working with the city of Renton to manage traffic on local streets near the freeway.
• Staffing WSDOT’s traffic management center during the busiest times.
• Putting extra WSDOT incident response trucks and staff in the area to quickly clear any blocking incidents.

We have created a Web page that has more detailed explanation of our work. www.wsdot.wa.gov/Projects/i405/RentonCulvertReplacement.

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