Mercer Corridor Project – Phase II

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Overview

Mercer West - Dexter Avenue North to Elliott Avenue West

The Mercer West Project will complete the City’s vision for a direct, two-way connection between I-5 and Elliott Avenue West continuing the segment of work constructed by the Mercer East Project. Along with new crossings of Aurora Avenue provided by the Alaskan Way Viaduct and Seawall Replacement Program , it will greatly enhance the connection between the South Lake Union urban center and the Uptown urban center, including Seattle Center.

The project includes:

• Widening Mercer between Dexter Avenue N and Fifth Avenue N, including the underpass at Aurora to provide three lanes in each direction, left-turn lanes, wider sidewalks, and a bicycle path;
• Converting Mercer Street to two-way operation with two lanes in each direction and turn pockets between Fifth Avenue N and Queen Anne Avenue N;
• Converting Roy Street to a two-way street with bicycle lanes between Fifth Avenue N and Queen Anne Avenue N;
• Creating a new Sixth Avenue N connection between Mercer and Harrison streets; and
• Closing Broad Street to re-connect the street grid between Ninth Ave N and Fifth Ave N.

The project team evaluated the feasibility and benefits of a second east-bound lane and sidewalk on West Mercer Place. No improvements are planned on West Mercer Place as part of this project.

Mercer Underpass (Dexter Avenue North – Fifth Avenue North)

Currently, the configuration for the Mercer Street underpass between Dexter Ave. N. and Fifth Ave. N. presents four eastbound traffic lanes with very narrow sidewalks. This project includes the widening of the Mercer underpass at Aurora Ave to allow for six travel lanes, turn pockets, wider sidewalks, and a bicycle path.

Existing underpass at Aurora:

• Four lanes (eastbound only)
• Five-foot sidewalks

Widened Underpass at Aurora (conceptual)

• Three lanes in each direction
• Median/left-turn lane
• Bicycle path
• 12-16 ft sidewalks

Sixth Avenue N. Alignment between Harrison St. and Mercer St.

The SDOT project team, in partnership with the Alaskan Way Viaduct and Seawall Replacement Program, evaluated options for the alignment of Sixth Avenue N. and are moving forward with the Seattle City Council approved design to curve Sixth Avenue N. around the future Gates Foundation campus. As shown in the graphic below, the street curves toward the east and around the campus, extending to a 'T' intersection with Mercer Street. There is no connection to Sixth Avenue N. north of Mercer Street.

Sixth Ave. N. Design Details

• Left turn from Sixth Ave N to westbound Mercer allowed
• Pedestrian crossings at Taylor and Dexter
• Pedestrian crossing over Mercer at Aurora

Fifth Avenue North to Fifth Avenue West – Convert Mercer and Roy streets to two-way operation

• Two lanes in each direction on Mercer Street (Fifth Ave N – Second Ave W)
• One lane each direction on Roy Street (Fifth Ave N – Queen Anne Ave N)
• Bike lanes on Roy Street
• All changes within the existing street right-of-way

West Mercer Place

The Mercer West Project Team completed evaluation and public outreach regarding options to improve traffic operations and pedestrian and bicycle connections on W Mercer Pl near Elliott Ave W.  The purpose of the evaluation was to determine if improvements are justified, based on the potential benefit (reduction in delay or travel times) and the estimated costs and impacts of such improvements. 

The Mercer West Team presented the alternatives and evaluation results at an Open House on March 15, 2011 and presented the evaluation to community organizations and other stakeholders in March and April to gather feedback on the alternatives and evaluation.  (see March-April 2011 entry in Project Updates Archive) 

Recommendations

The recommendations for West Mercer Place are based on the evaluation of traffic benefits, costs and impacts of the alternatives and the comments received from stakeholders and community members.  Recommendations are summarized by area of concern raised prior to and during the public comment period.

1. Traffic operations

• Extend the double left-turn lanes on Elliott Ave W
• No change to the existing merge/traffic lanes on W Mercer Pl at this time
• Continue to monitor traffic operations and make adjustments, if needed, on Elliott Ave W, Nickerson St, and Mercer St through Alaskan Way Viaduct Replacement and central waterfront (Alaskan Way and seawall) construction.  

2. Pedestrian and Bicycle Connection

• Support Parks Dept/FOLKPark effort to fund a pathway through the park to connect Uptown to Elliott Avenue West, by identifying grant and other funding opportunities.
• Construct a sidewalk on the southwest side of W Mercer Pl after waterfront construction is complete and once funding is available.

3. Pedestrian crossings on W Mercer St

• Enhance the pedestrian crossing at Fourth Ave W or Fifth Ave W by constructing curb bulbs or a pedestrian refuge island.
• Work with King County Metro to identify the appropriate stop locations for Rapid Ride and local bus service.

Project Benefits

With the proposed improvements on Aurora Avenue North that are part of the Alaskan Way Viaduct Replacement Project Bored Tunnel Alternative, the Mercer West Project will provide new, improved connections across Aurora Avenue N for all modes of travel.

• Keep people, goods and services moving
• Improve traffic flow by eliminating the extra turns required to get through the area
• Upgrade signals
• Reconnect streets to improve circulation
• Provide direct route to and from Seattle Center and Uptown
• Establish Mercer as a new transit corridor that can accommodate local and regional buses, including Rapid Ride service between Ballard, Uptown and Downtown
• Create safe, attractive pedestrian and bike connections
• Create safe, convenient crossings at intersections on Mercer and Roy streets
• Widen sidewalks on Mercer across SR 99
• Install bike lanes on Roy Street
• Add a bike path under Aurora along Mercer
• Build segments of the Lake to Bay Trail
• Improve freight connections
• Provide a direct route to Ballard and Interbay from SR 99 and I-5
• Add new option for freight to get to 15th/Elliott Avenue W
• Improve key intersections to accommodate large trucks
• Evaluate improvements to West Mercer Place near Elliott Avenue W
• Reconnect the Uptown and South Lake Union urban centers

Schedule

The Mercer West design is thirty percent complete as of April, 2011. Under the current schedule, Construction is not expected to begin until the fall of 2012, and will wrap up by the middle of 2015. With the completion of the Mercer West project, Broad Street will be permanently closed. In 2016, work will begin on the new street grid across Aurora (at John. Thomas and Harrison Streets).

More Information

If you have any questions or comments about the Mercer West project, please send us an email at mercerwest@seattle.gov

Thank you!