The massive yearlong "H-1 Rehabilitation" project got underway Sunday with a complete shutdown of the highway’s eastbound lanes from Likelike Highway to Ward Avenue.

The closure was in effect from 8 p.m. Sunday to 4 a.m. today.

An hour into the shutdown Sunday, eastbound traffic heading toward the closed freeway was light, and there was little congestion on the last off­ramp before the barricades.

Traffic along surface streets in the Kalihi and downtown areas was also relatively light.

The same stretch of highway will be closed again from 8 tonight to 4 a.m. Tuesday.

The much-needed, much-dreaded Department of Transportation project calls for repairing and repaving the 3.5-mile corridor between Middle Street and Ward Avenue, an expanse of heavily traveled highway that has not been repaved in 15 years.

In hopes that heightened public awareness would minimize the difficulty drivers may expect over the coming year, the department worked with hospitals, private businesses and community groups to spread the word about the project.

"We know that people won’t necessarily be happy about it, but we hope they will be understanding of the need for it," department spokes­woman Caro­line Sluyter said Sunday.

The complete overnight shutdowns — including the two scheduled this week plus 120 next year — will allow road crews to finish the work as quickly as possible, she said.

On most workweeks, Sunday through Thursday, crews will close one lane in each direction starting at 9 p.m., then close an additional lane at 11 p.m. This will leave one lane open in each direction. The lanes will reopen at 4 a.m.

Sluyter said the lane closures will likely result in "significant delays" of up to 20 to 30 minutes in drive time.

The department is advising southbound motorists coming from Red Hill and Moana­lua to take the airport viaduct to avoid slowdowns on the freeway.

Sluyter said island drivers have proved resilient and adaptable during previous major projects.

"The first few nights may be bad, but it should get better as people find alternate routes and adjust their schedules," she said.