New images have emerged showcasing California’s longest tunnel, which is being constructed to navigate around a landslide-prone area.
This 6,000-foot “Last Chance Grade” tunnel along Highway 101 in Del Norte County will be the largest underground road passage in the state’s history once it’s finished.
The chosen route through the hillside aims to circumvent up to four active landslide complexes and areas of shifting earthflows.
Caltrans recently hosted an open house allowing the public to view the designs and hear from a panel of specialists.
The tunnel project, which was approved back in 2014, will connect Crescent City and Eureka. This route is vital as it links Southern California to Oregon and beyond. However, the road has struggled with frequent disruptions for decades, largely due to landslides, steep oceanfront cliffs, and severe winter storms.
Officials noted that building this tunnel will help lower repeated emergency repair expenses, vehicle operating costs, and highway noise in Redwood National and State Parks, which attract around 2.5 million visitors each year.
The project’s official website mentioned that since 1997, repairing damages from landslides has cost over $100 million, including ongoing efforts.
Looking ahead, the official project timeline indicates that the final design, property acquisition, and environmental permitting will span from 2026 to 2031, with construction expected to kick off in 2031. The new bypass should be open to traffic by 2039.
“Last Chance Grade is more than a highway—it is a lifeline for the people, businesses, and emergency services of California’s North Coast,” commented Caltrans Director Dina El-Tawansy. She expressed that moving the tunnel into the design phase is a step closer to ensuring a safe, reliable connection for Del Norte County and travelers.
Overall, the project is anticipated to cost between $2.5 billion and $3.5 billion, though funding for the construction phase has yet to be secured. Officials believe that the construction will generate temporary jobs in various sectors, such as earthmoving, tunnel support, materials hauling, and environmental restoration.
