Mercer Corridor: Phase I of Converting Mercer Street to Two-way Traffic Begins Friday,

The Seattle Department of Transportation (SDOT) announces the beginning of Phase I of transitioning Mercer Street to two-way traffic beginning this Friday, May 2.

Traffic shifts to south side of Mercer
Street on Friday, May 2

Following the morning commute on Friday, May 2, the two eastbound traffic lanes on Mercer Street between First Avenue N and Fifth Avenue N will be shifted onto their permanent configuration on the south side of the roadway. This transition marks the beginning of Phase I of the transition to two-way traffic on Mercer and Roy streets. Following this switch, crews will begin to channelize the  north side of the roadway for westbound traffic.

Two-way traffic on Mercer Street between
First Avenue N and Fifth Avenue N begins the week of May 5

Once channelization is complete on the north side of the roadway, signal crews will begin converting intersections along Mercer Street to two-way traffic beginning at First Avenue N and working east towards Fifth Avenue N. The signal conversion process may take several days to complete and will likely begin towards the end of the week, weather permitting. Travelers are advised to pay close attention to street signs and expect an adjustment period for roadway users as intersections are converted to two-way traffic.

Roy Street, Queen Anne Avenue N restrictions begin the week of May 12

Following the opening of two-way traffic on Mercer Street between First Avenue N and Fifth Avenue N, Phase II will begin which includes converting Roy Street between Queen Anne Avenue N and Fifth Avenue N to two-way traffic. During this conversion, westbound Roy Street will be reduced to one lane while final channelization is put into place. Signals will be activated for two-way traffic on Roy Street starting at Fifth Avenue N and working toward Queen Anne Avenue N over a period of several days.

The final phase of converting Mercer Street to two-way traffic between Fifth Avenue N and Ninth Avenue N and closing Broad Street will likely occur immediately following Memorial Day in late May.

More information about traffic changes during each phase of construction can be found at: Information will be updated as the changes occur.

Throughout and after the roadway transition, construction impacts will be monitored and will include:

  • Monitoring traffic flow and adjust signal timing as conditions change throughout the corridor
  • Uniformed police officers stationed at key intersections to facilitate traffic flow
  • Additional signage and alternate route information will be available in advance

Continued communication throughout construction

SDOT will continue to provide coordinated construction outreach and updated construction timelines throughout the conversion to two-way traffic, including alternate route maps, email updates and a 24-hour hotline.

To learn more about upcoming construction, SDOT invites you to join the Mercer Corridor Project listserv. You can sign up on the project website: or call 206-419-5818 to join.

Contact:  Richard Sheridan, Communications Director, 206..684.8540