Washington State Department of Transportation (WSDOT) will close the mainline in either direction of Interstate 90 between the Mount Baker Tunnel and the Mercer Island Lid on Saturday, April 17 and Saturday, April 24 as crews test the fire suppression system in the tunnels.

During the closure, traffic using I-90 will use the reversible express lanes to get across Lake Washington.

· Saturday, April 17 – Crews will close the eastbound mainline of I-90 from 10 p.m. to 10 a.m. Sunday.

· Saturday, April 24 – Crews will close the westbound mainline of I-90 from 11 p.m. to 7 a.m. Sunday.

The fire suppression system will be disabled during the closure so drivers transporting flammable materials across Lake Washington need to use alternate routes such as I-405, State Route 522 or State Route 520. Drivers transporting flammable materials on westbound I-90 must exit at Island Crest Way (Exit #7) on Mercer Island. Eastbound drivers transporting flammable materials must exit at Rainier Avenue South (Exit #3) in Seattle.

Also this weekend, crews will close lanes on northbound I-5 between Boeing Access Road and I-90 starting at 11:30 p.m. on Friday and Saturday, April 16 and 17 to install high-tech electronic signs.

Crews will reopen the lanes at 6 a.m. on Saturday and 8 a.m. on Sunday. A signed detour will guide drivers northbound on Airport Way and back to I-5 via Edgar Martinez Way.

Drivers can check travel conditions by going to the Seattle traffic Web site at www.wsdot.wa.gov/traffic/seattle/ or by dialing 5-1-1.