OCEANSIDE, Calif. — Emergency repairs on the eastbound lanes of State Route 78 are officially underway and are expected to last about three weeks, Caltrans announced in a release on Friday.

Construction closures from College Boulevard to El Camino Real began last week after crews wrapped up about a month of work on the westbound side of the highway to replace metal culverts that collapsed amid the series of storms that swept through the area in March.

Caltrans said that crews will be working to replace a total of nine corrugated steel pipes with high density plastic and concrete pipes under the eastbound lanes.

The work and subsequent closures are estimated to continue for about three weeks. Crews will be working around the clock as possible to complete the needed repairs, the department said.

With the work on westbound SR-78, weather conditions posed a major obstacle for the work, prompting four extensions to the expected time of completion. On April 5, two of the three lanes were reopened for traffic.

Signs have been placed on the northbound and southbound Interstate 5 and 15 to warn drivers about the closure.

Motorists using the highway will be detoured at the SR-78 El Camino Real exit and directed to Vista Way and College Boulevard to the Plaza Drive eastbound entrance.

Real-time traffic information from Caltrans, including road closures, traffic speed and construction updates can be found on the agency’s QuickMap website.

The full cost of repairs to the stretch of SR-78 is estimated to be about $20 million, according to Caltrans, with funds for the repairs coming from the State Highway Operation and Protection Program.

Drivers are encouraged to avoid the area, if possible, while construction continues.