Rail construction will close Farrington Highway between Kualakai Parkway and Old Fort Weaver Road in both directions through April, meaning motorists who rely on that West Oahu stretch will need to use alternative routes and allow extra time in their commutes.

The closure will start at 10 p.m. Monday, according to the Honolulu Authority for Rapid Transportation, which is overseeing the project. The move is needed so that crews can move utility lines underneath that narrow stretch of roadway and lay the foundations for the columns that will eventually support the 20-mile rail project’s elevated guideway, HART officials say.

Drivers should access the H-1 freeway to the north or Kapolei Parkway to the south as alternative routes to Farrington. They should also allow extra time for those east-west commutes, although HART officials did not have estimates for how much time they should set aside. The semiautonomous government agency will coordinate with the city Department of Transportation Services to adjust traffic signal times to help ease the delays for detoured drivers, HART spokesman Scott Ishikawa said.

"The type of work that we’re doing takes up quite a bit of room," Kiewit Infrastructure West Co. spokeswoman Allison Andrade told the HART board Thursday. Kiewit, which is handling construction of the columns and guideway for the first half of the transit project, to Aloha Stadium, will coordinate with businesses in the area to reduce the disruption, including providing a shuttle for workers at Aloun Farms, she said.

Motorists will still be able to access the Kahi Mohala Behavioral Health facility in Ewa via Fort Weaver Road, according to a HART release.