Marin-Sonoma Narrows Project Nears Milestone

MARIN COUNTY, CA — Caltrans expects to reach a major milestone this month in the final phase of a decade-long lane widening project designed to reduce congestion along Highway 101 in Marin and Sonoma counties.

Crews are wrapping up paving and K-rail adjustments ahead of April 11, when Caltrans expects to shift traffic in both directions between Olive Avenue near Novato and San Antonio Road. Southbound traffic will be realigned off the temporary median lanes and onto the newly constructed roadway.

Meanwhile, northbound traffic will be realigned onto the temporary median lanes, allowing the next phase of construction to rebuild the old northbound section.

"This is the last remaining (HOV) lane construction project as part of the 16-mile US-101 Marin-Sonoma Narrows program," Caltrans said in a news release. "This project will complete and allow continuous HOV lanes on US-101 from Sausalito in Marin County to Windsor in Sonoma County."

The project included widening Highway 101 to install new northbound HOV lanes along 3.5 miles between Novato and the Marin-Sonoma line, along with 6.3 miles of southbound lanes from De Long Avenue to the county line.

Caltrans expects to open the new HOV lanes by next summer.