This blog post dives into a Capital Preventive Maintenance project that Caltrans is rolling out along US-101 in Marin County. It covers which towns are getting hit, what the nightly lane closures mean, and how folks in San Rafael, Larkspur, and Corte Madera can keep tabs as the work stretches through 2027.
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What this CPM project covers in Marin County
Caltrans is kicking off a Capital Preventive Maintenance program along US-101 from Wornum Drive to Corte Madera. The work affects communities in and around San Rafael, Larkspur, and Corte Madera as crews get started on rehabilitation along this busy stretch.
The first phase runs from Tuesday, May 12 through Friday, May 15, with lane closures each night. Southbound US-101 lanes close from 8 p.m. to 5 a.m., while northbound lanes close from 10 p.m. to 6 a.m., so anyone going to or from San Rafael and Larkspur toward Corte Madera will notice the changes.
For this first phase, Caltrans is setting the stage for bigger improvements down the road. The focus is on pavement rehabilitation to stretch out the road’s lifespan, not a total rebuild.
If you rely on US-101 in Marin County—especially if you’re commuting from Corte Madera to San Rafael or heading into downtown Larkspur—these nightly closures mean you’ll probably want to plan for alternate routes or tack on some extra travel time.
Phase details and long-term scope
Crews will remove old pavement striping, add temporary lane markings, and put up a median barrier for safety during this transition. Later, they’ll pave on- and off-ramps between the Wornum Creek Undercrossing and the Miller Creek Bridge, which is a pretty important connector for traffic moving through San Rafael and Corte Madera.
The project covers about 7.3 miles and includes 54.2 lane miles of improvements along the US-101 corridor. Caltrans is aiming to wrap up the entire thing by summer 2027, but honestly, Marin’s coastal weather could easily shift that schedule—especially near Mill Valley and those twisty roads that feed into 101.
Traffic impacts and safety considerations
Drivers should get ready for nightly lane closures as Caltrans tackles this maintenance work in Marin County. The most immediate impacts will hit the southbound lanes near San Rafael, Larkspur, and Corte Madera during the May 12–15 window.
Northbound traffic faces restrictions too, just on a slightly different schedule as crews move along the 7.3-mile segment that serves Marin’s busiest corridors.
- Southbound US-101 lanes close nightly from 8 p.m. to 5 a.m. during the initial phase.
- Northbound US-101 lanes close nightly from 10 p.m. to 6 a.m. in the same period.
- Watch for temporary striping, changed lane markings, and a new median barrier early on, with ramp work coming in later stages.
If you’re commuting from San Rafael neighborhoods like Terra Linda or downtown to Larkspur and Corte Madera, expect some delays and maybe look for alternate routes through Mill Valley or Sausalito if you can. Business corridors in San Anselmo and Fairfax might see some spillover traffic during peak hours, so it’s a good idea to keep an eye on real-time updates as this project rolls on through 2027.
Staying informed and planning your commute
Staying up to date matters for Marin County drivers dealing with this US-101 project. Caltrans offers reliable, around-the-clock traffic updates and real-time conditions, so you can plan around lane closures in San Rafael, Larkspur, and Corte Madera—or wherever you’re headed.
- Check 24/7 traffic updates at 511.org for live conditions and travel times around San Rafael, Larkspur, and Corte Madera.
- Use Caltrans QuickMap for real-time roadway conditions and closures along US-101 through Marin County, including Wornum Drive and Miller Creek Bridge corridors.
- Follow Caltrans District 4 updates on X (formerly Twitter), or call the statewide highway conditions hotline for Marin County-specific info.
Maybe you’re commuting to work in downtown San Rafael. Or you’re just heading to the waterfront in Larkspur.
Either way, planning ahead and checking Caltrans resources makes it easier to get through this multi-year pavement project. Local residents will eventually see better pavement and more durable travel along US-101, supporting safer, smoother trips for everyone—pedestrians, cyclists, and motorists from Corte Madera to San Rafael and every spot in between.
Here is the source article for this story: Multiple Lanes Scheduled to be Closed on Northbound, Southbound US-101 for Capital Preventive Maintenance Project in Marin County
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