Highway 12 Corridor
Improvement Project
Phase II, Stage 2

Project # C08002

Status: Complete


The State Route 12 Corridor Improvement Project Phase II Stage 2 consists of construction of pedestrian and bicycle facilities, roadway widening, asphalt pavement replacement, installation of curbs, gutters and sidewalks, stormwater treatment devices, pedestrian level street lights, and traffic signal modifications on State Route 12 between Agua Caliente Road and Boyes Blvd in the Springs Area of Sonoma Valley.

View/Download Bid Results (PDF)

View/Download Bid Tabulation (PDF)


State Highway 12, between Agua Caliente Road and Boyes Boulevard, just North of the city of Sonoma.


In 2010, important upgrades were completed on Highway 12 from Encinas Lane to Boyes Boulevard by the Springs Redevelopment Agency. In 2011, while the Agency was planning phase ll of the project from Boyes Boulevard to Agua Caliente, the state dissolved the redevelopment agencies - delaying forward progress for Phase ll of the project.

Although Highway 12 is a State Highway and not normally maintained by the County, the Board of Supervisors knew that upgrades were needed. The Board agreed to dedicate funding to complete Phase ll of the project.

Contact Information

Business Hours
Monday – Friday
8:00 AM – 5:00 PM

By Appointment Only.  Responding 24x7 to Emergencies.

Contact us by Phone
Office Location
La Plaza B
2300 County Center Drive
Suite B 100
Santa Rosa, CA 95403
38.462023, -122.725381

Standard Plans

Construction Standards for County Roads


Standard plans for construction of roads and related structures.