Two-Way Mercer Moves Closer to Reality

For decades, the “Mercer Mess” has been one of the City’s most significant transportation challenges.  Each day some 80,000 vehicles, along with growing numbers of pedestrians and bicyclists, enter and exit I-5 at Mercer Street, making it a critical east/west route for keeping people, goods, and services moving.  While eastbound traffic has had a straight shot on Mercer to I-5, the westbound traffic has been forced to follow the circuitous weave involving Valley and Broad Streets, as well as Fifth Avenue North and Roy Street.

SDOT will replace the SR 99 bridge over Mercer Street to provide for a widened, two-way Mercer with three lanes in each direction, wider sidewalks, and a bike path.

SDOT will replace the SR 99 bridge over Mercer Street to provide for a widened, two-way Mercer with three lanes in each direction, wider sidewalks, and a bike path.

After years of discussion and debate on how to best address the ”Mercer Mess,” the City is well on the way to implementing the Mercer Corridor Project, which will create a two-way Mercer Street all the way from I-5 to Elliott Avenue West.  In early 2010, SDOT began the construction on the eastern stretch of Mercer, the segment from Dexter Avenue North to I-5.  Last August, the newly widened Mercer between I-5 and Ninth Avenue North was opened to traffic.   Now, as construction on this eastern segment moves towards completion this summer, the focus is about to shift to the western segment.

Next Friday evening, May 17, construction to widen the roadway between Fifth Avenue North and Ninth Avenue North and replace the SR 99 bridge over Mercer Street will begin.  SR 99 between Valley Street and the southern end of the Battery Street Tunnel will be fully closed for that weekend, as will Mercer itself between Fifth Avenue North and Dexter.  When traffic is reopened to both the following Monday morning, May 20, traffic on SR 99 will have been shifted to the west side of the street over Mercer Street maintaining two lanes in each direction, and Mercer itself in this stretch will be reduced to two eastbound travel lanes. 

Eastbound travel on Mercer between Fifth Avenue North and Dexter will remain in this two-lane configuration throughout the West Phase of the project, which is anticipated to be completed in mid-2015.  

Once completed, a two-way Mercer Corridor will improve mobility for all modes of transportation:Mercer w_AuroraUnderpassRESIZE

  • Creating an efficient and direct east/west transportation corridor
  • Providing a key connection to the north portal of the SR 99 deep bore tunnel, which will replace the Alaskan Way Viaduct and Battery Street Tunnel
  • Reducing conflicts between all modes of travel
  • Improving pedestrian and bicycle safety and access
  • Strengthening connections among area neighborhoods
  • Improving access to and from Seattle Center
  • Accommodating and encouraging future transit investments 

For additional information on the project and updated information on construction impacts, visit the project website. http://www.seattle.gov/transportation/mercercorridor.htm.