Work on two major roadways is expected to have a ripple effect for traffic on both sides of Lake Washington starting next Friday, March 27, and continuing until Monday morning, March 30.
In Seattle, the State Route 99 Alaskan Way Viaduct will be closed during daylight hours Saturday and Sunday for a semiannual inspection. Contractor crews working on the SR 99 Tunnel Project, the Mercer Corridor Project and Seattle Public Utilities (SPU) will take advantage of the closure to complete utility and sign bridge installation work.
Lane closures along both directions of SR 99 begin at 7 p.m. Friday. By 10 p.m., SR 99 will be closed between the south end of the Battery Street Tunnel and Valley Street until 5 a.m. Monday.
In addition, drivers heading across Lake Washington from the Eastside will see westbound Interstate 90 detoured to the express lanes as crews upgrade tunnel operations systems inside the westbound Mount Baker and Mercer Island tunnels.
“With no major events this weekend, it’s the perfect time to bundle up these needed roadway closures,” said Traffic Engineer Mark Bandy. “Even so, we still expect traffic will be heavy. Drivers can help keep traffic moving by carpooling, taking transit or delaying discretionary trips.”
SR 99 closure details
7 p.m. Friday, March 27, until 5 a.m. Monday, March 30
• SPU crews will close two northbound lanes and one southbound lane of SR 99 between Ward Street and Highland Drive from 7 p.m. Friday to 5 a.m. Monday.
• WSDOT and SDOT contractor crews will close SR 99 between the Battery Street Tunnel and Valley Street from 10 p.m. Friday to 5 a.m. Monday.
6 a.m. to 6 p.m. Saturday, March 28, and Sunday, March 29
• WSDOT bridge inspection crews will conduct a scheduled inspection of the Alaskan Way Viaduct between Spokane Street and the Battery Street Tunnel.
Westbound I-90 closure details
11 p.m. Friday, March 27, until 5 a.m. Monday, March 30
• Contractor crews will shift all westbound I-90 traffic between Bellevue Way and Rainier Avenue South to the express lanes from 11 p.m. Friday to 5 a.m. Monday.
• Drivers wishing to access Mercer Island will need to exit westbound I-90 at East Mercer Way. There are no westbound exits to Mercer Island from the express lanes.
• Those wishing to travel from Mercer Island to Seattle should enter the express lanes at 77th Avenue Southeast or Island Crest Way.
• Westbound I-90 drivers will be unable to exit to Rainier Avenue South and should follow the signed detour via Fourth Avenue South and South Dearborn Street.
• Drivers needing to transport flammable materials westbound across Lake Washington must use alternate routes such as Interstate 405 or state routes 520 or 522.
Special events:
PBR Rodeo at Key Arena
• 8 p.m. Friday, March 27
• 6:50 p.m. Saturday, March 28
Taste Washington! at the CenturyLink Field Events Center
• 2 p.m. daily Saturday, March 28, and Sunday, March 29
WSDOT needs help from drivers to keep traffic moving
Drivers should plan ahead for construction and create a commuting strategy:
• Allow extra time to travel through the work zone or on alternate routes.
• Ride transit, carpool or use other alternate forms of transportation.
• Travel early in the morning or later in the evening, or reschedule discretionary trips.
Project background
The viaduct is closed twice yearly to allow WSDOT bridge inspectors to conduct an in-depth safety inspection designed to make sure the aging road remains safe for drivers.
The I-90 closure is the second of up to 30 weekend-long directional closures as part of WSDOT and Sound Transit’s I-90 Two-Way Transit and HOV Operations project, which is adding carpool lanes to both directions of I-90 between Seattle and Bellevue. This collaboration will preserve the number of general purpose lanes for solo drivers while adding all-day carpool lanes to I-90. Building the new HOV lanes on the outer roadway of I-90 will enable construction of Sound Transit’s 14-mileEast Link light rail extension from Seattle to Redmond.
