There’s no rest for weary motorists this weekend, as a full closure of the Highway 520 toll bridge follows last weekend’s disastrous snarls on neighboring I-90.

The shutdown is scheduled from 11 p.m. Friday until 5 a.m. Monday, extending across Lake Washington between I-5 in Seattle and 92nd Avenue Northeast in Clyde Hill, according to the Washington State Department of Transportation. The floating bridge bicycle lane will remain open.

Contractors will continue to build the giant Montlake Boulevard lid and interchange, along with a future carpool-bus flyover that lands onto the express lanes on Interstate 5. The project includes a landscaped walk-bike overpass, which will create a more pleasant link between the Washington Park Arboretum and the University of Washington.

This weekend’s job involves shifting the highway lanes, so that work can start on the Montlake lid high-occupancy vehicle exit, and extend the lid farther west, a WSDOT video update said.

The shutdown will complicate traffic going to Mariners baseball games Friday evening, and Saturday and Sunday afternoons. Sounder commuter trains will carry fans to and from the Sunday ballgame, which begins at 1:10 p.m. against the Oakland Athletics.

Beforehand, there will also be an overnight closure of the westbound Seattle exits to Montlake Boulevard and Lake Washington Boulevard, from 10 p.m. Thursday until 6 a.m. Friday, to adjust lid girders that had been lowered a few inches from their correct alignment, WSDOT said.


WSDOT has permanently closed a two-year temporary ramp that carried cars from the Madison Park area into eastbound 520, via Lake Washington Boulevard East, as of Thursday. Those drivers must now use the Montlake Boulevard ramps.

However, all mainline and collector-distributor lanes of I-5 in Sodo will stay open this weekend, except one off-ramp (see below).

In other roadwork:

  • The exit-only lane from southbound I-5 to the West Seattle Bridge and Columbian Way will close from 10 p.m. Friday until 5 a.m. Monday, for expansion joint replacement.
  • Southbound I-5 exits to Mercer Street, from both the mainline and the express lanes, will close from 9 p.m. Friday until 4 a.m. Monday, for ongoing construction of the future bus-carpool lane in the I-5 express lanes, linking Highway 520 to job centers in South Lake Union. Crews will work on drainage and retaining walls near Mercer.
  • On the south side of Lake Stevens, Highway 9 will close for roundabout construction at 20th Street Southeast, from 9 a.m. Thursday until 4 a.m. Monday. Detours will be marked via Highway 204 and Highway 2.
  • In Tacoma, Highway 167 will close Friday, Saturday and Sunday overnights beneath I-5, while crews demolish vestiges of the former Puyallup River bridge. The ramp from southbound 167 to southbound I-5 will close from 9 p.m. Friday until 4 a.m. Monday. Detours will be marked.

Last weekend, Highway 520 itself filled with miles of stop-and-go traffic while drivers diverted from a clog on I-90 at Mercer Island. Motorists flooded the island, and were sometimes stuck a few hours Friday night, while all mainline lanes were closed above the island’s western shore for expansion joint replacement. Drivers blamed WSDOT for allowing traffic into a virtual dead-end, and for inadequate notice despite traffic alerts, and messages on 16 overhead signboards.

Travelers can find updates through WSDOT apps, social media and construction websites. A partial menu is listed here, and a real-time traffic flow map is here.

Unlike last weekend’s I-90 joint repairs, the Highway 520 lane closures have clear starting and ending locations, like past Montlake disruptions that drivers know.