Interstate 90 travelers should plan for overnight lane closures through Mercer Island due to construction activities this week. Crews working for WSDOT and Sound Transit are adding HOV lanes to the I-90 outer roadway and new ramps on I-90 between the cities of Mercer Island and Bellevue.

Monday through Friday this week I-90’s reversible express lanes will close nightly from 8 p.m. to 6 a.m. for construction. They will reopen in the westbound direction.

In the mainlines Monday through Friday, one or two lanes in various locations of both westbound and eastbound I-90 from 8th Avenue S. to just north of 150th Avenue SE will close each night for electrical work. The first lane will close at 7 p.m., and the second lane closes at 9 p.m. All lanes will reopen by 5 a.m.

On the same days, two lanes on westbound I-90 just west of East Mercer Way will close for construction work. The first lane will close at 8 p.m. and the second lane will close at 9 p.m. All lanes will reopen by 5 a.m.

Looking ahead:

* Sunday, Oct. 31: I-90 express lanes will run in the westbound 3:30-5:30 p.m., then will reverse to eastbound direction 6:30-10 p.m.

* Sunday, Oct. 31: I-90 express lanes will close 11 p.m. to 6 a.m. for construction. Express lanes will reopen westbound.

* Monday, Nov. 1 through Thursday morning, Nov. 4: I-90 express lanes will close nightly from 8 p.m. to 6 a.m. for construction. They will reopen in the westbound direction.