101 Prairie Creek Curve Improvement Project

Caltrans proposes to improve an existing, non-standard compound curve on U.S. Highway 101 from postmile (PM) 125.20 to 125.62 in Humboldt County. The purpose of the project is to improve safety and reduce the frequency and severity of collisions. The project is needed because this segment of the highway experiences a higher rate of collisions than the statewide average.

Project Description

The proposed work consists of a curve realignment and shoulder widening to improve the geometrics of the roadway through the curve. The existing curve is a compound curve with a larger radius of 800 feet and a smaller radius of 350 feet. The highway consists of two 12-foot lanes and 2-4-foot shoulders. Three build alternatives have been identified to realign the existing curve. The alternatives differ between two simple curve alignments and a compound curve alignment. One alternative proposes retaining walls along the north and southbound shoulders. The other two alternatives include a single retaining wall along the southbound shoulder. Both alternatives propose to remove and replace the four existing culvert systems in the project limits and construct two new systems (PM 125.39 and 125.52).


At this time, Caltrans anticipates beginning construction by 2025.

Estimated Traffic Impacts

A lane closure will be required with one-way traffic control during construction. Bicyclists will be accommodated.

U.S. 101 two-lane roadway at postmile 125.20 to 125.62 in Humboldt County.

U.S. 101 two-lane roadway at postmile 125.20 to 125.62 in Humboldt County.

Current view of project area