In order for the Washington State Department of Transportation to conduct important maintenance work, it has announced that Interstate 90 westbound will be closed from Island Crest Way to the Interstate 5 interchange beginning at 10:30 p.m. this Friday until about 6 a.m. the following morning. The city of Mercer Island noted that Islanders should plan ahead and travel at alternate times or take an alternate route if travel is necessary during this period.