Photo from Google Maps.

Caltrans Press Release:

A seismic retrofit project at the Westhaven Drive Undercrossing Bridge and the Sixth Avenue Overcrossing Bridge on US Highway 101 near Westhaven is scheduled to begin with placement of temporary guardrail on Monday, November 18. Work hours are 7:30 a.m. to 4:30 p.m., weekdays. Traffic will be restricted to one lane in each direction of travel, and motorists may experience minor traffic slowdowns. Bridge work will consist of reinforcing bridge columns. 

This seismic retrofit project will also include work at the Trinidad Road Undercrossing Bridge beginning in January 2014. The contractor is Golden State Bridge, Inc. of Martinez. 

The project is estimated to be completed by summer 2014. Please watch for bicyclists when traveling through the area, and remember to Slow for the Cone Zone.