This weekend, Interstate 90 detours return again with a westbound closure, allowing the Washington State Department of Transportation (WSDOT) to undertake light rail preparations inside the Mt Baker and Mercer Island tunnels.

Starting at 11 p.m. on Friday, WSDOT will funnel westbound traffic to Seattle to the center express lanes for construction purposes. The closure will end by 5 a.m. Monday.

All westbound drivers wishing to exit onto Mercer Island must use East Mercer Way, but will have the option to continue through the interchange back onto the right lane of I-90, in order to exit at Island Crest Way. Drivers wishing to reach Seattle from MI must enter the express lanes at Island Crest Way or 77th Avenue Southeast. View the closure map here.

Other upcoming weekend lane reductions are: May 5–8 (westbound) and May 12–15 (eastbound). Click here for more.

In addition, weather-permitting, WSDOT will begin the work involved to restripe the general purpose roadways in both directions to accommodate a future HOV lane. The new lanes will not open to traffic until June 3, the same date as the permanent closure of the center roadway for light rail construction.