Alternative A1 (Rudisill Road to LCG Tunnel)
This alternative, which includes a 2,000-foot tunnel under Del Norte Coast Redwoods State Park, is 3.2 miles long at a cost of $680 million and would impact old growth redwoods. Project timeline: three years.
Alternative A2 (Rudisill Road to Damnation Trailhead)
Also 3.2 miles, this route goes through old growth forest and includes a 115-foot high, 1,100-foot long bridge through the tree canopies to reduce its impacts. The cost is $275 million. Project timeline: two years.
Alternative C3 (Rudisill Road to South of Mill Creek Access)
This project has a footprint of 245 acres, three times larger than the A options. The 8-mile route, which avoids old growth trees, includes a 1,680-foot tunnel. The cost is $980 million. Project timeline: three years.
Alternative C4 (Rudisill Road to North of Mill Creek Access)
The second longest option at 8.6 miles, this route also avoids old growth, but has a 265-acre footprint, 10 water crossings and would impact mature redwood forest. Cost is $1 billion. Project timeline: four years.
Alternative C5 (Rudisill Road to Hamilton Road)
At nearly 12 miles, this is the longest and most expensive of the proposed routes. It avoids old growth, but impacts 93 acres of mature redwoods within its 330-acre footprint. Construction would include 11 bridges and a 1,680-foot tunnel. Cost is $1.25 billion. Project timeline: four years.
Alternative F (Full Tunnel)
One of the most technically challenging, this alternative is a 1-mile tunnel to bypass the Last Chance Grade slide. While it has the smallest footprint at 4.5 acres, it also has the longest timeline at 6.5 years. The cost is $1.05 billion.
Maintain Current Route
Under this alternative, Last Chance Grade will require regular maintenance and emergency restoration projects as needed to address changing conditions, with a projected cost of approximately $26 million by 2034. A large, deep slide could result in a major failure and complete closure of the roadway indefinitely. Some potential options closest to the existing alignment include a retreat upslope that could require cutting more than 100 old growth trees.