The Seattle Department of Transportation (SDOT) reminds travelers that the first of two full weekend closures of SR 99 and eastbound Mercer Street will begin this weekend as part of the Mercer Corridor Project. Weekend closures will occur the following weekends in December:
- December 6 – December 9 (SR 99 and eastbound Mercer Street)
- December 13 – December 16 (SR 99 and eastbound Mercer Street)
The two closures in December will provide for completion of critical Mercer Street widening and SR 99 bridge replacement work to meet an important deadline allowing for construction of the SR 99 Bored Tunnel’s North Portal in June of next year. Please note that work is weather dependent and may be cancelled and rescheduled for later dates if inclement weather occurs.
Preparatory work on SR 99 and eastbound Mercer Street: December 5 and 6
In preparation for the full weekend closure of SR 99 and eastbound Mercer Street, crews will reduce SR 99 to a single northbound lane between Harrison Street and Valley Street tonight, December 5 from 7:00 p.m. to 5:00 a.m. tomorrow morning. This will allow crews to complete early saw cutting along the curb lane on SR 99 in preparation for this weekend’s traffic switch. One lane of northbound SR 99 will remain open to traffic.
Additionally, eastbound Mercer Street between Fifth Avenue N and Dexter Avenue N will be reduced to one lane under the SR 99 bridge over Mercer Street on Friday, December 6 from 10:00 a.m. to 1:00 p.m. as crews expose a corner of the Mercer Street wall footing in preparation for the weekend closure. One lane on eastbound Mercer Street will remain open to traffic.
SR 99 and eastbound Mercer Street full weekend closure: Friday, December 6 through Monday, December 9
SR 99 and eastbound Mercer Street will be fully closed to traffic beginning Friday, December 6 at 11:59 p.m. to Monday, December 9 at 5:00 a.m. as Mercer Corridor Project crews shift traffic from the western side of the SR 99 bridge over Mercer Street to the newly constructed eastern portion of the bridge. This will allow for demolition of the western side of the existing bridge the following weekend. During the closure:
- SR 99 will be fully closed to traffic between Valley Street and the southern end of the Battery Street Tunnel. Traffic traveling through Seattle via SR 99 will be directed to I-5 in northern Seattle at 85th Street or in southern Seattle at E Marginal Way and Spokane Street. More information about alternate routes during construction may be found at: http://www.seattle.gov/transportation/mercercorridor.htm.
- Eastbound Mercer Street will be fully closed to traffic between Fifth Avenue N and Dexter Avenue N. Traffic heading east toward I-5 from Queen Anne will be detoured to eastbound Broad Street via Harrison Street and will reconnect to Mercer Street at Ninth Avenue N to continue towards the I-5 ramps at Mercer Street.
- The sidewalk on Mercer Street will also be closed between Fifth Avenue N and Dexter Avenue N. Pedestrians will be detoured to Broad Street.
- Broad Street and the I-5 on- and off-ramps at Mercer Street and westbound Mercer Street will remain open during the weekend work.
Please note, on Monday, December 9 when SR 99 and eastbound Mercer Street re-open to traffic, SR 99 will be in a new configuration with two northbound lanes and two southbound lanes located on the new bridge structure. Additionally, access to Roy Street from southbound SR 99 will be closed. Alternate access to destinations west of SR 99 may be reached by using Valley Street.
Early warning signs will be available in advance of the SR 99 lane restrictions and eastbound Mercer Street detours. Travelers can expect significant traffic and delays and should plan ahead and use alternate routes.
Access to Seattle Center from I-5 via westbound Mercer and Broad streets and from southbound SR 99 at Valley Street will be open through the weekend.
Contact: Rick Sheridan, 206.684.8540