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Ramp, Lane Closures on Southbound US-101 as Part of Marin Sonoma Narrows B7 Project in Marin County

Published:

Schedule: Tuesday, Oct. 14 through Friday, Oct. 17 from 9:30 p.m. until 7:30 a.m.

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Marin County — Caltrans has scheduled electrical work on Southbound US-101 for the Marin Sonoma Narrows B7 project from Tuesday, Oct. 14 through Friday, Oct. 17 from 9:30 p.m. until 7:30 a.m. the next mornings.

Cars traveling Southbound on US 101 as work continues as Part of Marin Sonoma Narrows B7 Project in Marin County.

The work will take place just north of Rowland Boulevard, extending to the Marin County/Sonoma County line.

The Atherton Avenue off-ramp is scheduled to be closed on Wednesday, Oct. 15 during the aforementioned time frame. The Atherton Avenue on-ramp and De Long Avenue off-ramp are scheduled to be closed on Thursday, Oct. 16, and the De Long Avenue on-ramp is scheduled to be closed on Friday, Oct. 17.

Lane closures will take place from Tuesday through Friday during that same time frame.

Detours for Atherton on and off-ramp closures on Southbound US-101

  • Atherton on-ramp closure: Drivers should travel Southbound on Redwood Boulevard and enter US-101 at De Long Avenue
  • Atherton off-ramp closure: Drivers should exit at De Long Avenue, turn right and use Redwood Boulevard

Detours for De Long on- and off-ramp closures on Southbound US-101

  • De Long on-ramp closure: Drivers should travel Southbound on Redwood Boulevard and enter Southbound US-101 at Rowland Boulevard.
  • De Long off-ramp closure: Drivers should exit at Atherton Avenue and then use Redwood Boulevard to reach De Long Avenue

All work depends on weather. Daytime access will be available for motorists.

On Monday, Sept. 29, Caltrans has opened the long-awaited, continuous HOV lanes (third lanes) on Northbound and Southbound US-101. This work removed merges on Northbound US-101 (just north of Atherton Avenue) and Southbound US-101 (south of Kastania Road), which opened three continuous lanes through the project limits.

Construction for the project includes widening US-101 to install HOV lanes for 3.5 miles along the northbound lanes from North Novato to the Marin, Sonoma line, and for 6.3 miles along the southbound lanes from De Long Avenue to the county line.

This is the last remaining High Occupancy Vehicle (HOV) lane construction project as part of the 16-mile US-101 Marin-Sonoma Narrows (MSN) program. This project will complete and allow continuous HOV lanes on US-101 from Sausalito in Marin County to Windsor in Sonoma County.

For 24/7 traffic updates, please visit 511.org: https://x.com/511SFBay
For real-time information, visit Caltrans QuickMap: https://quickmap.dot.ca.gov
Follow us on X: https://x.com/CaltransD4
Or call 1-800-472-7623, 1-800-427-ROAD for state highway conditions statewide.