Tunnelbuilder Promoting the world's tunnelling industry to a huge qualified audience

View the Spanish Tunnelbuilder website View the Italian Tunnelbuilder website

USA/California - Caltrans Selects Tunnel Alternative for Last Chance Grade Project

26/06/2024

Last Chance Grade (LCG) is a 4.83 km (3-mile) segment of US 101 just north of Wilson Creek, between Klamath and Crescent City. Landslides and road failures have been an ongoing problem for decades and substantial funds have been invested in repairs. The road is currently safe to use, but a long-term solution is needed to ensure continued safe and reliable transportation on U.S. Highway 101. 

In a significant step toward securing a long-term solution at Last Chance Grade, Caltrans has selected Alternative F, a 1.82 km (6,000-foot) tunnel that bypasses area landslides and realigns the highway, in a move that is essential to advancing the Last Chance Grade Project efficiently. The proposed tunnel - along U.S. 101 in Del Norte County, California - would be the longest constructed in Caltrans history. 

With construction estimated to cost around EUR1.96 billion (USD2.1billion) in 2031 dollars, the tunnel avoids chronic landslides, coastal erosion, and the impacts of climate change while ensuring safety during seismic events. While the option presents challenges due to the sensitive environment and potential impacts on large-diameter, old-growth redwood trees, Caltrans is committed to delivering a successful project through partnership, community support, and collaborative mitigation efforts, exploring all avenues to stay on schedule while prioritizing quality, efficiency, and preservation. 

Caltrans continues to seek all possible funding opportunities to realize this project. The project has remained on schedule and on budget and the project team is on track to finalize its environmental document by late 2025. Further design refinements would occur in the coming years. To keep on track, the project would need to fund design, support, right-of-way acquisition, and other costs by December 2025, and it would need to fund construction costs by 2029. If all goes according to plan, construction could begin as early as 2030. If that happens, the tunnel could be open as early as 2038, however, Caltrans is looking for any and all opportunities to accelerate this timeline. 

A solution at Last Chance Grade has been desired for decades. The announcement of a preferred alternative follows the February release of the project’s Draft Environmental Impact Report and Environmental Impact Statement (EIR/EIS), including a Draft Section 4(f) Evaluation. These documents were the culmination of extensive engineering and scientific studies, strengthened by far-reaching collaboration. Visit https://dot.ca.gov/ and https://lastchancegrade.com. 26/24.



NEED QUALIFIED PERSONNEL?