Beginning Friday, July 18, up to three westbound lanes of the freeway will be closed 24 hours a day while contractors working for the state Department of Transportation replace two aging and deteriorating 92-foot-long bridge expansion joints on the East Channel Bridge.
The lane closures will also affect traffic on many of the Eastside's key commute corridors including I-405 and Highway 520, says DOT spokesperson Kris Olsen.
Transportation officials are urging drivers to make alternate plans such as carpooling, vanpooling, telecommuting, using an alternate route or adjusting their schedule to take advantage of off-peak travel times.
Traffic engineers estimate more than half of the 85,000 drivers that use westbound I-90 each day will need to use another route or an alternate travel mode to keep travel times at one hour or less from Issaquah to Seattle.
"We need drivers to change the way they commute for seven days so that WSDOT can complete this important safety work," said DOT Traffic Engineer Mark Bandy. "We will see backups from this work, but if enough drivers do their part we can keep them manageable."
Traffic engineers estimate the best times to travel will be before 6 a.m., between 11 a.m. and 2 p.m. and after 7 p.m. on the affected days.
Olsen said westbound I-90 will be reduced to one through lane near Bellevue Way from 9:30 p.m. Friday, July 18, to 5 a.m. Friday, July 25.
Three lanes of westbound I-90 will be open at the Bellevue Way interchange as the ramps from Bellevue Way and I-405 join mainline I-90.
The westbound I-90 HOV lane will be open to all between I-405 and the east entrance to the center roadway.
Complete lane closure information and animated maps are available on the project website.