Caltrans District 4 Solano County Newsletter

Solano experienced one of the biggest interruption in traffic this summer. The Westbound span of the Carquinez Bridge on I-80 was shut down for a weekend. It started at 8 PM on Friday, August 21, 2026, where lanes where closed down one at a time until full closure at 10 PM.

(New asphalt being poured on to the bridge)

( Maintenance taking care of an over grown tree)

From there construction crews got to work on grinding the top layer of asphalt concrete and begin the preparations for the pour.

Caltrans is all about innovation and the asphalt concrete is like none other. The mix used on the bridge deck is made to last for approximately 20 years. It also helps with the waterproofing and prolongs the bridge structural integrity. Motorist in turn experience a safer and smooth ride.

Full closures can be very intrusive in anyone’s day to day, but we at Caltrans try to take full advantage of the opportunity and during this closure Caltrans Maintenance Crews came out and worked on tasks that can be completed from the closure limits, from Highway 780 to the base of the bridge. This includes vegetation removal, graffiti removal, repairs and other tasks.

For more info visit: Carquinez Bridge | Caltrans

To sign up for future mailing that concern the Carquinez Bridge visit: Carquinez Mailing List

SR 37/Fairground Diverging Diamond Interchange Project

On July 7 2026, in the City of Vallejo the Bay Area welcomed its very own diamond. The Diverging Diamond, or DDI, is a unique transportation configuration where motorist end up on the opposite side of the road, so to say. Its unique transition lends it self to help motorist either get on the freeway or continue on local roads with the least amount of resistance.

July 7th marked the completion of the DDI, where it brought together transportation authorities, community, and elected officials to celebrate. Caltrans Director, Dina El-Tawansy came and spoke to the invitees of the Ribbon Cutting along with Congressman, Jon Garamendi, MTC Commissioner for Solano County, Mitch Mashburn, District 1 Supervisor, Cassandra James, Mayor of Vallejo, Andrea Sorce, and Six Flags Discovery Kingdom, Park Manager Bill Mullen. The community was represented by special speaker, Mac Mall along with the kids of The Country Club Crest, a neighborhood that patiently waited for the DDI’s completion.

During the celebration many of the attendants experienced the multimodal options the DDI offers. Unlike other DDIs this one has safety features that make it safe for all types of transportation. Bicyclist can experience safe bike lanes and pedestrians can experience the walking path that traverses through the middle of the diamond. The completion of the State Route 37/Fairgrounds is the beginning of more to come with State Route 37.

This project was designed by Caltrans, successfully brought to completion by our partners in the Solano Transportation Authority, and celebrated by the Vallejo citizens.

To read more about this project head here:
STA Diverging Diamond Website

And if you want to read more on State Route 37 and what Caltrans has planned for the corridor:
SR37 Corridor Projects | Caltrans

Lastly, to watch an amazing video about the DDI head here:
Fairgrounds DDI Vallejo

State Route-29 Pavement Rehabilitation and Complete Street

(New light signal being installed)

(A completed bulb out)

State Route 29, also known as Sonoma Boulevard, in Vallejo is making some head way. This project has seen its fair share of challenges, but it is nothing crews aren’t ready to work through. Shortage of material, some unexpected rain delays, and design conflicts that had to be resolved have made their appearances in this project, but in the last couple of weeks crews have been filling in curbs, standing up new lighting poles, and preparing for the highly anticipated paving of 6 mile route. Once the paving starts it will be a straight to the end.

Work is expected to complete Winter of 2026

Take a look at an animation created to see what to look forward to once the project is complete. State Route– 29 Animation

For more information on this project please go to our website - State Route 29 (SR-29)/Sonoma Boulevard Vallejo Pavement Rehab and Complete Streets Project | Caltrans

Setting the PACE: Public Affairs Customer Engagement Site is Now Live!

District 4 is proud to announce the launch of our new Customer Service Request (CSR) platform. PACE, the Public Affairs Customer Engagement site, provides a regularly updated breakdown of services requested and rendered across the district.

• The CSR dashboard aims to provide an overview of the responsiveness to maintenance services requested across the nine Bay Area counties.
• The data represented as month-to-date falls within a rolling 30-day Service Level Agreement (SLA) and is updated weekly.
• We strive to close 60% (or more) of all monthly service requests received via the CSR website portal.
• For more information or to leave comments/suggestions, please contact D4CSLTEAM@dot.ca.gov.
• To report a highway issue/problem, please submit a CSR ticket through the Customer Service Request Form.