Highway 1 will be closed to thru traffic between Jalama Road and Santa Rosa Road near Lompoc from 9 a.m. until 6 p.m. Wednesday to allow the installation of a girder on the Salsipuedes Creek Bridge.
Motorists traveling in either direction will detour using Highway 246, a Caltrans spokesman said.
Highway 1 will remain open for local traffic between the Highway 1 interchange with Highway 101 and Jalama Road, with access maintained to Jalama Beach County Park, the spokesman said.
In addition to the girder installation, the Salsipuedes Creek Bridge Replacement Project includes construction of a retaining wall and fish passage.
CalPortland Construction of Santa Maria is the contractor for the $5 million project, which is expected to be complete in summer 2021.
A traffic signal operating 24 hours a day through May 2020 will maintain one-way reversing traffic control, and those driving larger vehicles are advised the width of each lane has been reduced from 12 feet to 11½ feet, the spokesman said.