Caltrans is closing Highway 116 under Highway 101 in Petaluma Monday due to construction work.
The highway will be closed in both directions from 10 p.m. to 5 a.m. nightly through Thursday morning.
The closure is needed to demolish the old Highway 101 overpass, which is being widened to accommodate carpool lanes, Caltrans said.
The work was scheduled for last week, but was rescheduled due to bad weather. The work could be delayed again if wet weather persists, Caltrans said.
During the closure, motorists can detour on Caulfield Lane and South McDowell Boulevard.