The Seattle Department of Transportation (SDOT) is beginning Phase I of its Mercer Street transition to two-way traffic on Friday, May 2. 

Following the morning commute on Friday, May 2, the two eastbound traffic lanes on Mercer Street between First and Fifth avenues North will shift onto their permanent configuration on the south side of the roadway. Following this switch, crews will begin to channel the north side of the roadway for westbound traffic. 

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 and working east toward Fifth Avenue beginning the week of May 5. The signal conversion process may take several days to complete and will likely begin toward 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. 

Following the opening of two-way traffic on Mercer Street between First and Fifth avenues, Phase II will begin the week of May 12, which includes converting Roy Street between Queen Anne and Fifth avenues North to two-way traffic. During this conversion, westbound Roy Street will reduce to one lane while final channelization is put into place. Signals will activate for two-way traffic on Roy Street starting at Fifth Avenue and working toward Queen Anne Avenue over a period of several days. 

The final phase of converting Mercer Street to two-way traffic between Fifth and Ninth avenues North 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; and

•Additional signage and alternate route information will be available in advance.