Mercer Corridor Project update: Fifth Avenue N and Thomas Street intersection to open this week

The Seattle Department of Transportation is pleased to announce the intersection of Fifth Avenue North and Thomas Street will soon be in its final configuration and Thomas Street will be open at Fifth Avenue North. Travelers can expect the following changes and construction throughout the corridor:

Crews will place the intersection of Fifth Avenue North and Thomas Street in its final configuration by the end of the day Thursday, Aug. 13. Uniformed police officers will be stationed at the intersection between 9 a.m. and 3 p.m. to help facilitate traffic and pedestrian flow while crews place signals in their final configuration. Once signal work is complete, traveler can expect the following:

Thomas Street will reopen at Fifth Avenue North.

  • Drivers traveling west on Thomas Street will have the option to turn right or left onto Fifth Avenue North.
  • Drivers turning left from Thomas Street may also access Broad Street toward the Elliott Bay Waterfront.
  • The relocated driveway on the west side of Fifth Avenue North at Thomas Street will be open for deliveries to the Seattle Center Campus.

All pedestrian crosswalks in this area will reopen.

Pedestrians crossing the Seattle Center driveway at Thomas Street should watch for the signal and only cross the driveway when the

Eastbound Broad Street will continue to operate with two left-turn lanes at Fifth Avenue North (no right turns allowed).

Please be mindful of changes and send any questions to

What’s next?

The Mercer West Project will install a large stormwater detention pipe in Roy Street between Fourth Avenue North and Fifth Avenue North in September and October. This is recently added work that provides stormwater detention for the area including the Washington State Department of Transportation’s construction at the future SR 99 tunnel north portal. Details about this closure may be found on the project website.

Intermittent lane closures will continue through fall as crews complete miscellaneous improvements throughout the project area. Closures will be temporary, localized, and occur during non-peak hours, Monday through Friday.

Looking ahead

Adaptive signal control is under design and expected to be installed on Mercer Street in 2016. The new system will be more responsive to traffic conditions, but will still be limited by the capacity at the I-5 on-ramps during the peak periods.

As a reminder, questions and concerns can be sent to or our 24-hour construction hotline at (206) 419-5818.