Confusion Hill Realignment - Purpose and Need

There has been a recurring problem of landslides and slipouts around Confusion Hill on Route 101 in northern Mendocino County over the last decade. A large, ancient rock slide complex extends from the South Fork of the Eel River to more than 1,000 feet above, enveloping the current highway, 140 feet above the river. This slide activity has caused numerous road closures and delays associated with one-way traffic control situations. Geotechnical studies of the site have concluded that the ancient slide is progressively losing strength with a high probability that the slides within the complex will continue to move in the future.

In August of 2003, Caltrans negotiated with the Federal Highway Administration and received approval for funding for the relocation of Route 101 at Confusion Hill. Since that time a value analysis was conducted to identify project options, constraints, alternatives and the various impacts and costs that be associated. The process ultimately identified six alternative alignments and involved many project stakeholders to ensure that various interests were represented. Studies were then conducted of these six alternatives for preparation of the projects environmental document. From this process, the most cost-effective alternative with the least environmental impact was presented.