One-way Traffic Control begins on State Route 121 in Sonoma County To Replace Bridge Railings on the Yellow Creek Bridge

Four-month closure Monday, November 3, 2025 - Saturday, February 28, 2026

Sonoma County - Caltrans will implement one-way traffic control on State Route 121 in the Schellville community of Sonoma County to replace bridge railings on the Yellow Creek Bridge, located several hundred feet south of the newly opened Route 116/121 Roundabout at Big Bend.

The closure begins just after midnight (12:01 AM) Monday, November 3, 2025, and last until 5:00 AM Saturday, February 28, 2026. During this period, the two-lane roadway will be reduced to one lane as northbound and southbound alternate passage through the work zone.

The project schedule is based on typical rainy season conditions in Sonoma County. The contractor will work under a permit that protects the creek from sedimentation and other construction impacts.

The Yellow Creek Bridge was built in 1922. The bridge railings are part of the original structure, serving as guardrails to keep vehicles from veering off the bridge. The weather-worn railings must be replaced to meet current safety standards.

A traffic study and multiple meetings with local first responders were conducted to evaluate construction options. The study compared a full closure with a long detour via Routes 101 and 37 to the proposed one-way traffic control. Based on traffic impacts and emergency access considerations, the one-way traffic control was determined to be the safest and least disruptive option.

This work represents the second phase of a two-bridge safety improvement project. Caltrans recently finished replacing the railings on the Arroyo Seco Bridge on SR-121 near 8th Street, reopening the bridge last night, October 27, around 10:00 PM.

Caltrans thanks motorists and the local community for their patience as we continue to improve bridge safety and infrastructure in Sonoma County.

Please visit Caltrans QuickMap: https://http://quickmap.dot.ca.gov or follow Caltrans on Twitter at: https://twitter.com/CaltransD4

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