Get ready for some night moves, drivers. Those using US-101 Northbound through Marin County should brace for some slowdowns, thanks to ongoing construction work on the stretch between Novato and the county's northern border with Sonoma. According to Caltrans, the nocturnal activity will necessitate ramp and lane closures. The San Antonio Road off-ramp is particularly affected, slated to shut down on December 7 from 10 p.m. to 4 a.m. on December 8.
During these construction-heavy hours, at least one lane will remain accessible for traffic, somewhat mitigating the inconvenience to travelers. Despite the nocturnal disruptions, daytime drivers will have full access near San Antonio Road, weather permitting. Those hitting the northbound lanes can detour via the Petaluma Boulevard/South Kastania Road exit as a workaround for the San Antonio off-ramp closure.
The Marin-Sonoma Narrows B-7 construction project is more than a mere inconvenience—it's claimed to be the last High Occupancy Vehicle (HOV) lane undertaking as part of the grander 16-mile US-101 Marin-Sonoma Narrows program. Completion's in sight, with summer 2025 marked as the green light for these new dedicated lanes.
In the thick of the project is the widening of US-101. It's about creating space for those 3.5 miles of HOV lanes along the northbound route from North Novato to the Marin and Sonoma county lines. Not to mention the additional 6.3 miles on the southbound, stretching from De Long Avenue to the line. This June, Southbound US-101 traffic rolled onto new elevated lanes, showcasing the project's progress, starting over San Antonio Creek and extending just north of Atherton Avenue in Novato.
With orange cones and construction workers a common sight, motorists are urged to tread carefully and mind the speed limits in these zones. Patience is a virtue especially appreciated by Caltrans, who've conveyed their thanks for drivers' understanding during this state highway, bridgework, and maintenance stretch. For those dependent on real-time traffic updates, 511.org and Caltrans' own QuickMap service are but a click away.
