Caltrans says tunnel is preferred long-term fix for Last Chance Grade on US 101

Del Norte County — Caltrans on day two of the March 2025 California Transportation Commission meeting presented an update on the Last Chance Grade project on U.S. 101, saying the agency has selected an alignment that includes a one‑mile tunnel, a north bridge and a south approach to bypass repeated landslide failures at the ocean edge.

The presentation said the site, roughly 10 miles south of Crescent City, is threatened by four large active landslides and coastal erosion that have repeatedly closed or restricted the highway since the road was built in 1937. Caltrans corridor manager Jamie Magnoli said the chosen “Alternative F” best meets the project’s purpose and need and is intended to reduce long‑term maintenance and protect reliability for residents, tribal nations and regional commerce. “A stable new roadway built to current standards will improve safety here,” Magnoli said.

Caltrans Deputy District Director Richard Mullin told commissioners the agency received $50 million for the environmental phase in 2019 with an annual update condition and expects to finish the final environmental document in December 2025. Mullin and Magnoli said the project remains on schedule and within the $50 million environmental budget; design and permitting are planned through 2030 with construction anticipated to begin in 2031 and conclude by 2039 under the current timeline. Caltrans said it will pursue a construction manager/general contractor delivery method to accelerate work by roughly one year where possible.

The team emphasized the project’s complexity: the alignment crosses coastal and sensitive resource areas, old‑growth redwoods and tribal ancestral lands and will require federal and state permits. Magnoli said the environmental document will be a combined federal/state review at the highest National Environmental Policy Act/CEQA level and that permitting—particularly for drilling and geotechnical work needed to refine the tunnel design—is likely to be on the project’s critical path through 2030. “It’s a very complex environmental document,” Magnoli said, adding permits from the California Coastal Commission, state fish and wildlife agencies and the Regional Water Board will be required.

Caltrans said the preferred alternative reduces environmental impacts in some areas by shifting alignment and by bridging wetlands at the north portal, but acknowledged the northern portal will affect large‑diameter old‑growth trees. The preferred concept includes an operations and maintenance center and other measures to limit resource impacts.

Caltrans also reported an historical investment of more than $125 million to maintain the current alignment, including nearly $100 million in the last decade. The agency said temporary repairs such as retaining walls have restored two‑way traffic after years of single‑lane operations, but that repeated repairs are not sustainable.

Public comments and elected officials’ letters were noted in support. Tamara Layton, executive director of the Del Norte Local Transportation Commission, told the CTC the region views U.S. 101 as its only direct connection to the rest of California. “US 101 is our only direct connection to California, and it’s our lifeline highway,” Layton said.

Caltrans said near‑term priorities include finalizing mitigation agreements with stakeholders and tribes, procuring a construction manager/general contractor and independent cost estimator, completing permits and securing construction funding. Agency staff acknowledged construction costs are conceptual and will be refined when construction management and final design firms are onboarded.

Why it matters: The Last Chance Grade corridor has no practical detour—Caltrans said alternate routes add at least six hours between Crescent City and Eureka and even longer for tribal communities—so a permanent solution affects safety, tribal access, local economies and regional connectivity.

What’s next: Caltrans will complete the final environmental document in December 2025, pursue permitting and final design through 2030, and aims to begin construction by 2031 pending funding, permits and contractor procurement. The agency requested continued Commission oversight and funding collaboration to advance the project.