Schedule: Monday, Aug. 3 to Friday, Aug. 7 from 8:30 p.m. to 6:30 a.m.
Marin County — Caltrans has scheduled ramp and lane closures for final striping on Northbound and Southbound US-101 for the Marin Sonoma Narrows B7 project from Monday, Aug. 3 through Friday, Aug. 8 from 8:30 p.m. until 6:30 a.m. the next mornings.

The schedule for ramp closures is as follows:
Monday, Aug. 3 through Friday, Aug. 7: The San Antonio on- and off-ramps on Northbound and Southbound US-101 will be closed.
Wednesday, Aug. 5 through Friday, Aug. 7: The Atherton Avenue and De Long Avenue on- and off-ramps on Southbound US-101 will be closed.
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 has completed and allows continuous HOV lanes on US-101 from Sausalito in Marin County to Windsor in Sonoma County.
All work is weather dependent.
Detours for San Antonio on-ramp closures on US-101
- Northbound: Drivers must enter on US-101 southbound at San Antonio Road, exit at the Atherton Avenue off-ramp and then re-enter US-101 northbound.
- Southbound: Drivers should take Northbound US-101 and exit at Kastania Road, turn left and re-enter Southbound US 101.
Detours for San Antonio Road off-ramps on US-101
- Northbound: Drivers must exit at Petaluma Boulevard South/ Kastania Road, enter US-101 southbound, and exit at San Antonio Road
- Southbound: Drivers should continue southbound and exit at Atherton Avenue, turn left and enter Northbound US-101 to get to the San Antonio off-ramp.
Detours for De Long on-ramp and off-ramp closures on Southbound US-101
- On-ramp: Drivers should travel Southbound on Redwood Boulevard and enter Southbound US-101 at Rowland Boulevard.
- Off-ramp: Drivers should exit at Atherton Avenue and then use Redwood Boulevard to reach De Long Avenue.
Detours for Atherton Avenue on and off-ramp closures on Southbound US-101
- On-ramp: Drivers should travel Southbound on Redwood Boulevard and enter US-101 at De Long Avenue
- Off-ramp: Drivers should exit at De Long Avenue, turn right and use Redwood Boulevard.
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.
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