The Washington state Department of transportation is adding a lane in both directions of Interstate 405 between State Route 167 and State Routed 169.

The project also includes construction of a new half-diamond interchange at State Route 515 (Benson/Talbot Road) and a new Benson Road bridge over I-405.

Here are the construction traffic impacts for the coming week:

I-405 mainline

• Friday, Oct. 29 – the morning of Saturday, Oct. 30 – One lane of southbound I-405 between SR 169 and SR 167 will close at 11 p.m. and reopen by 6:30 a.m.

• Saturday, Oct. 30 – the afternoon of Sunday, Oct. 31 – The carpool lane will close in both directions of I-405 between SR 167 and Sunset Boulevard at 8 p.m. The lanes will re-open at 2 p.m. Sunday.

• Monday, Nov. 1 – the morning of Friday, Nov. 5 – One lane of southbound I-405 between SR 169 and SR 167 will close nightly at 9 p.m. for construction work. The lane will open at 4 a.m.

I-405 ramps

• Friday, Oct. 29 – the morning of Saturday, Oct. 30 – The off-ramp from southbound I-405 to southbound SR 167 will close nightly from 11 p.m. to 6:30 a.m.

• Friday, Oct. 29 – the morning of Saturday, Oct. 30 – The off-ramp from southbound I-405 to northbound SR 167 will close nightly from 11 p.m. to 9 a.m.

• Monday, Nov. 1 – the morning of Friday, Nov. 5 – The off-ramp from southbound I-405 to north and southbound SR 167 will close nightly from 11 p.m. to 4:30 a.m. for construction work.