California Department of Transportation

Mad River Bridges Replacement - Purpose and Need

The north and southbound Mad River Bridges are structurally deficient and are at the end of their useful life. River flows have scoured the pier footings exposing and undermining the bridge foundations. Additionally, the bridges do not meet current seismic guidelines, and the lane and shoulder widths do not meet current design guidelines.

The first bridge crossing the Mad River at this location was a covered wood structure constructed in the early 1900ís replacing the ferry system of the late 19th century that provided access across the river. The roadway was converted from a county road to a state highway in 1921 and Caltrans replaced the wooden bridge with a steel truss structure in 1929. The bridge carried both north and southbound traffic until a separate southbound bridge was constructed in 1958 as part of the Route 101 freeway bypass of McKinleyville. That same year, the northbound bridge was restriped to provide two traffic lanes to accommodate the new alignment. Seismic work was performed on the southbound bridge in 1987 and, since that time, only minor maintenance activities have occurred on both bridges.