Interstate 90 between Seattle and Mercer Island will close eastbound late Saturday night, so workers can repair and replace lights.

The shutdown, from Interstate 5 across Lake Washington to Island Crest Way, will go from 11:30 p.m. Saturday until 7:30 a.m. Sunday.

The work involves routine bulb replacements that happen every two years, within both the Mount Baker Tunnel and the Mercer Island lids, said spokesman Joe Calabro of the Washington State Department of Transportation.

Traffic Lab is a Seattle Times project that digs into the region’s thorny transportation issues, spotlights promising approaches to easing gridlock, and helps readers find the best ways to get around. It is funded with the help of community sponsors Alaska Airlines, Kemper Development Co., Madrona Venture Group, NHL Seattle, PEMCO Mutual Insurance Company and Seattle Children’s hospital. Seattle Times editors and reporters operate independently of our funders and maintain editorial control over Traffic Lab content.

Detour options include the Highway 520 toll bridge, or going around the lake using Highway 522 or I-405. Mercer Islanders will still be able to enter the freeway at Island Crest Way, or the high-occupancy ramp at 80th Avenue Southeast, to travel east into Bellevue.

In other traffic disruptions, a long-term closure of Highway 203, forcing drivers to detour at Carnation Farm Road between Carnation and Duvall, continues until mid-January, as workers replace drainage lines where the roadway buckled last winter.

On the Seattle waterfront, four-lane Alaskan Way South will be shifted farther inland onto a new concrete roadbed, from south King to Columbia streets this weekend from Friday night until Monday morning. Traffic lanes will remain available throughout the changeover. Ferry customers will keep their existing lane next to Elliott Bay, from Pier 48 into the Colman Dock terminal.

Next week from Monday to Thursday, weeknight closures from 11 p.m. to 5 a.m. are planned in the I-5 exit northbound to Northeast 130th Street. Sound Transit contractors are building an overhead passenger platform and trackway for a proposed future light-rail station.