Work starting today to replace 4.5 miles of old Interstate 5 median barrier will close up to two lanes of both the north and southbound freeway at night between Mounts Road in DuPont and Berkeley Avenue in Lakewood.
The work will start in DuPont and move north, and should finish by mid-October, according to the Washington State Department of Transportation.
The project requires that the inside lane of both north and southbound I-5 be closed simultaneously to make room for workers and equipment, and sometimes that two lanes in one direction be shut down.
The northbound lane can close at 8 p.m. and the southbound lane can close an hour later. A second lane in one of those directions can close at 11 p.m.
Northbound lanes have to reopen by 5 a.m., and southbound lanes by 6 a.m.
Exceptions to that schedule include Friday nights, when southbound lanes cannot start closing until 10 p.m. Crews can keep one northbound lane closed until 8 a.m. on Saturday mornings.
The project should replace about 2,500 feet of barrier each night.