SAN DIEGO (CNS) - All southbound lanes of Interstate 5 will be closed from 9:30 p.m. to 5 a.m. starting Sunday night and continuing through Oct. 25, according to the San Diego Association of Governments.

The closure is the first of two five-day closures during which Caltrans crews will remove temporary wooden structures supporting a bridge over I-5 at Gilman Drive. Work crews will also finish constructing the bridge during that time. I-5 southbound will be closed from the Interstate 805 interchange to La Jolla Village Drive and significant delays are expected.

"The overcrossing and related roadway improvements will connect Gilman Drive to the west and Medical Center Drive to the east," according to SANDAG. "The project will provide a vital link between the west and east campuses of UCSD and add a second on-campus crossing over I-5."

The bridge is being constructed as part of the Mid-Coast Trolley Blue Line Extension, with an 11-mile extension of trolley service by the Metropolitan Transit System from Santa Fe Depot in downtown San Diego to University City. Construction on the extension, including the new bridge, began in 2016 and is scheduled to be completed in 2021.