State Department of Transportation work on the H-1 Freeway may have been the source of extremely heavy traffic late at night this week.
Drivers experienced bumper-to-bumper traffic in the westbound direction in the late evening every night this week even though there were no accidents or stalled vehicles.
The DOT said road closures were in effect this week for the "PM Contraflow Project."
From Monday night through Thursday morning, barrier installation work closed two to three left lanes, between the Pearl City onramp to the Waipahu offramp, from 8 p.m. to 4:30 a.m. The closures were to install zipper lane barriers.
But on Thursday night, two right lanes will be closed, from the Pearl City onramp to the Waipahu offramp, from 8 p.m. Then, three lanes will be closed until 4:30 a.m. Friday. Crews will be working on deck widening and glider installation.
There will not be any late-night road closures over the weekend, state officials said, but left-lane closures will resume starting Monday.
The state has been making progress on adding an additional lane on the freeway, and part of the new lane is already open past the Waimalu exit. DOT spokesman Tim Sakahara said the new lane has already been making a difference on the traffic flow.
"It has made a tremendous impact," Sakahara said. "We are looking to open the full lane the end of September, weather permitting."