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State Route Projects

State Route 12 West - Jameson Canyon

All Significant Work Completed - Late 2014

Caltrans has a new webpage for the Highway 12-Jameson Canyon Project. It includes maps, pictures, factoids and links to the Caltrans Twitter page.

CTC Allocates Funds for Jameson Canyon Widening Project 8/10/11 

The Solano Transportation Authority (STA) in cooperation with the Napa County Transportation and Planning Agency (NCTPA) and Caltrans has completed the preparation of the final Plans, Specifications, and Estimates (PS&E) for the SR 12 Jameson Canyon project. All required right of way acquisitions are complete. All required environmental permits have now been secured.

The SR 12 Jameson Canyon project constructs two new lanes, median concrete barrier, and standard inside and outside shoulders on both the new and existing lanes.  The length of the project is approximately 5.8 miles and limits on Route 12 are from PM 0.0 to 3.3 in Napa County and from PM 0.0 to R2.6 in Solano County.  The STA, Caltrans, and Napa County Transportation Authority (NCTPA) officially broke ground on the project on April 4, 2012.  The Napa County segment is scheduled for completion in August 2013. The Solano County segment is scheduled to be completed by June 2015.

The California Transportation Commission (CTC) at its August 10, 2011 meeting approved a construction funding allocation of $61M, fully funding the project. The project is funded with a combination of Proposition 1B Corridor Mobility Improvement Account (CMIA), Regional Transportation Improvement Program (RTIP), State Interregional Transportation Improvement Program (ITIP), State Transportation Improvement Program (STIP), Traffic Congestion Relief Program (TCRP) and Federal Surface Transportation Program (STP) funds.

Total project cost is approximately $139M including environmental mitigation, design, right of way acquisition, utility relocation, construction and associated support costs. Construction cost is estimated at approximately $90M. The project has been divided into two separate construction packages in Napa and Solano counties respectively.

Download the SR 12 Jameson Canyon 2012 corridor map:

Download the Initial Study with Proposed Mitigated Negative Declaration (CEQA) and Environmental Assessment (NEPA) for SR 12 Jameson Canyon Road Widening Project.



Jameson Canyon Website Update 4-14-14

All major work for the Napa County portion of Jameson Canyon has been completed and is open to traffic.  The Solano County portion of Jameson Canyon is currently undergoing construction and is expected to be completed and open to traffic by August 2014.

These photos are courtesy of Caltrans District 4 Photography, copyright 2014.  Taken June 2013 - April 2014.




Jameson Canyon Media Tour 7-23-14

Caltrans hosted a media tour to observe firsthand the application of Shotcrete (spray concrete) to construct the natural-looking sculpted retaining wall.  In Solano County, portions of the 3-tiered wall stand 10 stories tall. The Shotcrete is applied and is sculpted by hand within one hour of application.  It is then followed up by carving 'crevices' into the wall and then stained to blend into the natural landscape.

The wall is expected to be finished the last week of July in preparation for traffic-lane switching to accommodate the installation of the concrete median on the Solano side of the project.  Caltrans anticipates opening the roadway to traffic in early September.


SR Three Phases of the Shotcrete Process: Shotcrete over rebar (right); top layer of Shotcrete (middle); freehand sculpting to resemble natural rock (left)



The 3-tiered 'rock' wall stands 10 stories tall in Solano County.  Traffic still flows above and below where the sculpting is being done.


Rebar structure (right) before Shotcrete is applied and sculpted (left)



The final layer of Shotcrete is sprayed just before sculpting begins


The Shotcrete is sculpted freehand within one hour of spraying before it dries



Boulderscape VP Todd Presho describes the Shotcrete process to the media






All Significant Work Completed

State Route 12 East - Safety Projects

EngineeringThe STA, working closely with law enforcement agencies and Caltrans, has developed a multi-faceted strategy for improving safety and mobility on this important interregional highway route from Rio Vista to Suisun City and Fairfield. The four key elements of the program are enforcement, legislation, public education and signage, and engineering.

Click here for more information.

State Route 12 East/Church Road Improvements

EngineeringProject Study Report: Caltrans, in partnership with STA, has completed a study of the proposed improvements at the intersection of SR 12 and Church Road-Amerada Road. The improvements include the addition of right turn/eft turn lanes and acceleration/deceleration lanes along SR 12 in the east-west directions, the addition of left turn lane on Church Road approach and realignment of the intersection to eliminate the offset between Church Road and Amerada Road.

Download the complete SR 12 East/Church Road PSR (11.7MB)


Envinronmental Document Completed and Adopted: In November 2016, Caltrans and STA adopted a Negative Declaration Initial Study Report.  This report found no sigificant impacts from this proposed project.  The Initial Study Negative Declaration can be found here:

Download the ISND Environmental Report

State Route 37 Studies and Resources

SRSolano County, in conjunction with Napa, Sonoma, and Marin Counties, are studying the feasibility for the improvement of SR 37 to be more adaptable to sea level rise and to ease congestion on certain stretches that are only 1 lane in each direction.  As a vital east-west connector, issues need to be identified, stakeholders communicated with, and options for improving SR 37 considered.  A fact sheet for the project can be found here: SR37 Fact Sheet.  You can find a presentation from August 24th to Caltrans here: SR37 Update Presentation to Caltrans

The Sonoma County Transportation Authority's Hwy 37 Website offers additional information as well.  

Below is a list of recent studies and resources regarding the condition and potential future conditions of SR 37.

***Update April 2018***

On April 11, 2018 the STA Board accepted the SR37 Transportation and Sea Level Rise Corridor Improvement Plan.  This plan includes typical corridor concept elements: goals and objectives, corridor issues, potential strategies for improvements, an implementation plan and next steps.  This plan was built upon previous studies completed by UC Davis and Caltrans and highlighted the corridor's environmental sensitivity, vulnerability to flooding and congestion.  It also framed the magnitude of potential cost for transportation improvements on the corridor. 

The objective of the Plan was to introduce corridor concepts that will be further analyzed as part of three distinct segments of the corridor.  Solano County is included in Segments B (SR 121 to Mare Island Interchange) and Segment C (Mare Island to I-80).  The plan also identified Segment B as the priority segment for improvements related to sea level rise and congestion.  This was a precursor to begin developing a Caltrans' required Project Initiation Document (PID) followed by the environmental phase for transportation improvements within Segment B.


***Update March 2018***

On March 14, 2018, the STA Board adopted the STA Guiding Principles for the SR 37 Corridor environmental process. The full text of the principles can be viewed here

***Update December 2017***

SR 37 SURVEY  We need your feedback!

To help us improve your safety and experience on SR 37, please take a few minutes to complete a survey online: 

Enter to win a $25 gift card. When you have completed the survey, you can enter a drawing to win a $25 gift card. 


***Update October 2017***

Informational Open House on the Highway 37 Improvement Plan

SRIn response to impacts from sea-level rise, flooding and increased traffic along the corridor, the counties of Marin, Napa, Sonoma and Solano, in partnership with Caltrans and the MTC, are planning to improve access and safety along Highway 37.

The Open Houses:

  • Informed residents and Highway 37 users about the status of the planning process
  • Provided an opportunity for participants to share their concerns and provide feedback

Monday, Oct. 2nd
Mayor Bob Sampayan welcomed about 75 members of the public to the Vallejo Naval and Historical Museum who came to learn more about the Highway 37 Corridor Improvement Planning process.

Our facebook page has photos from the evening of information.

The 3 other participating counties held Open Houses during September.

Contact Daryl Halls, STA Executive Director, 707-424-6075, with questions regarding this meeting.

Download meeting flyer.


September 20th Open House in Novato:

Here is KRON Channel 4's 3-minute video coverage of the SR 37 open house meeting held September 20th in Novato:



***Update February 2017***

Due to heavy and persistnent rains duing the month of January, SR37 was closed for flooding for 13 days. Caltrans provided an update about the flooding to the STA Board on February 8th.  The presentation can be viewed here: Caltrans Update on SR37 Flooding 



***Update December 2016***

The SR 37 Policy Committee have met twice and unanimously recommended that the Sonoma, Napa, and Marin CMAs participate with financial contributions on the STA's SR 37 P3 Corridor Study.  However, this recommendation also included a broader scope with a modified title of SR 37 Corridor Financial Opportunities Analysis. 

In summary, the modified scope of work is for a consultant or consultant team to act as a financial advisory resource for the SR 37 Policy Committee as the committee continues to investigate financial opportunities to improve the corridor.  The scope includes case study examples of P3 and full privatization finance options, a decision making toolkit for pursuing any one of those financial examples, and a planning level toll revenue forecast.

The expanded scope of work is estimated for the SR 37 Corridor Financial Analysis is $85,000; however, STA's budget share would decrease overall by $20,000 based on the following four County CMA contributions: SR

  • NCTPA $15,000
  • TAM $20,000
  • SCTA $20,000
  • STA $30,000 (previously $50,000)

Total:  $85,000


SR37 Status Update Powerpoint 12-14-16


***Update October 2016***

On October 12th, 2016 the STA Board approved a partnership with the Transportation Authorities of the Counties of Marin, Napa and Sonoma, and MTC to develop a State Route 37 Transportation and Sea Level Rise Corridor Improvement Plan. STA is also seeking to partner with Caltrans to conduct Public Outreach for the plan. SR