Caltrans will reduce a portion of state Highway 1 in Pacifica to one-way traffic for five days beginning this morning, officials said.
The highway will go down to one lane of traffic about a half-mile south of Linda Mar Avenue from 7 a.m. to 3 p.m. every day though Friday, according to Caltrans.
Crews will be building a new concrete wall on a hill above the southbound lane that has been prone to rockslides.
Work is scheduled to wrap up on Friday afternoon, officials said.
Drivers are advised to expect delays and leave extra time to drive through the area.