State Highway 1 in Marin County just north of the Sonoma County line is closed until around 7 p.m. today for bridge construction, Caltrans officials said.
The highway will be closed from Valley Ford Road to the north to Tomales Petaluma Road to the south. Workers are pouring concrete on a section of a bridge deck of the new Estero-Americano Bridge in Marin County.
The new bridge will have improved height clearance over the flood-prone creek below, according to Caltrans.
Motorists will be detoured around the construction at Tomales Petaluma Road and Valley Ford Road and back onto Highway 1. Delays are expected and motorists should consider taking alternate routes, Caltrans officials said.
Bicyclists will be detoured off Whitaker Bluff Road and Middle Road.