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Released by: Transportation & Public Works
For Immediate Release

Highway 12 Southbound Detour on June 18th, 2015

Santa Rosa, CA  –  June 9, 2015  –  On June 18 th , 2015,southbound traffic on Highway 12 will be detoured onto Madrone Road, Arnold Drive, and Verano Avenue from 9 am - 8 pm. There will be access to homes and businesses throughout the detour. The detour will allow PG&E to complete an essential tie-in of their transmission lines for the Highway 12 Improvement Project. 

"This tie-in marks a major milestone in the PG&E pipe relocation at the Highway 12 and Sunnyside location," explained Sonoma County Board of Supervisor Susan Gorin. "Excavation is one of the loudest parts of the relocation of utilities, and we are happy that this milestone means there are quieter nights ahead for nearby residents."

Detour Details:

  • Time:  9 am - 8 pm
  • Route:  from Highway 12 southbound, right on Madrone Road, left on Arnold Drive, and left on Verano Avenue.
  • Delays:  Signals on Arnold Drive will be adjusted to improve traffic flow, however motorists should expect delays between 15 and 30 minutes. 

There will be flaggers at each intersection of the detour. California Highway Patrol will be present at the intersections in peak commute hours from 3 pm - 7 pm. Drivers will be alerted to the changed conditions with roadside message boards. At 8 pm the detour will end, and traffic controls will resume the current practices of alternating traffic with one way lane closures.

Many utilities, such as PG&E, have utility lines that run under Highway 12. To make room for structural enhancements to the road, some utilities have to be relocated. Caltrans requires work located within the traffic lanes to occur at night when a lane can be closed. PG&E requires a continuous 22-hour work period to complete the tie-in. To accommodate the long work shift, and provide the best option for motorists, the combination of a daytime southbound detour and nighttime alternating traffic was selected.

This is the first of two tie-ins that must be completed by PG&E. The second tie-in, located at Fetters Creek and Highway 12 is scheduled for July  9 th. It is likely that the same detour method and timing will be used for the Fetters tie-in.

This is a key milestone in the Highway 12 Improvement Project, which will bring pedestrian and bicycle facilities, roadway widening, asphalt pavement replacement, installation of curbs, gutters and sidewalks, and many more upgrades to Highway 12 between Agua Caliente Road and Boyes Blvd in the Springs Area of Sonoma Valley. 

Sonoma County Transportation and Public Works and their partners would like to thank Highway 12 users and the people living and working in the Fetter Hot Springs - Agua Caliente community for their patience. Please contact David with Transportation and Public Works at 707- 565-2533 with any questions.

Our Mission:  to plan, build, manage, and maintain Sonoma County's investment in quality services and infrastructure.  

Our Vision:  Leading the way to a safe and sustainable community through stewardship and innovation.


Contact Information

Johannes J. Hoevertsz


Transportation & Public Works
Business Hours
Monday – Friday
8:00 AM – 5:00 PM
Contact us by Phone
Office Location
La Plaza B
2300 County Center Drive
Suite B 100
Santa Rosa, CA 95403
38.462006, -122.725384