SR37/Fairgrounds Dr., Vallejo: STA & Caltrans Reaching Milestone Interchange Opening

May 5, 2026

Date: 5 May 2026
Agency: Solano Transportation Authority, Caltrans District 4-Bay Area
Contact:  Sean Person, Contact:  Sabrina Martinez
Phone: (707) 399-3217, Phone: (510) 934-5257

State Route 37 (SR 37)/Fairgrounds Drive Interchange in Vallejo:
Solano Transportation Authority and Caltrans
Reaching Major Milestone with New Interchange Opening

SOLANO COUNTY  – The Solano Transportation Authority (STA), in close coordination with its transportation partner, the California Department of Transportation (Caltrans), is in the process of completing construction work on the new State Route 37 (SR 37)/Fairgrounds Drive Interchange Project in Vallejo. The interchange improvement project will enhance motorist safety and improve bicycle and pedestrian access with construction of a new Diverging Diamond Interchange.

This is the first-ever Diverging Diamond Interchange (DDI) constructed in the Bay Area and only the second-ever constructed on a major highway in California.

What to Expect:
The new DDI is anticipated to open to traffic on Saturday, May 16, weather dependent. Work is underway and will involve overnight closures:

• All closures are scheduled overnight on Friday, May 15 into the morning of Saturday, May 16. Closures are anticipated to occur from 9 p.m. until 9 a.m.
•  Motorists on Fairgrounds Drive at SR 37 should watch for temporary traffic lane shifts and follow all on-site signage.
• The eastbound and westbound on and off-ramps at SR 37/Fairgrounds Drive will be closed overnight with detours.
• Fairgrounds Drive will also be closed to traffic overnight from Sage Street to Gateway Drive in Vallejo.
• Please follow on-site signage for detours and see the embedded map for additional closure information.
• Final construction, including final striping, will continue after the opening of the new Diverging Diamond to traffic.

We appreciate the public’s cooperation and patience as important work on this important project continues! Motorists should drive with caution in construction zones, slow down for worker safety and expect travel delays. All work is weather dependent.

Diverging Diamonds are Safer and Easier to Access
The Diverging Diamond Interchange will provide a safer, easier entrance to Vallejo while improving accessibility for residents and businesses near the SR 37 and Fairgrounds Drive corridor. The project will improve flow of traffic in the area, reducing delays and creating a simpler interchange to navigate safely.

The DDI supports increased connectivity to regional transit, the greater Vallejo area, and employment and recreation centers, including Six Flags/Discovery Kingdom. Additionally, the project will allow bicyclists and pedestrians a more direct bike path to Vallejo from surrounding communities, such as American Canyon and Napa.

Navigating the DDI is easy, just follow the road! Watch the informational video available on the STA website or at the link below for more information.

To learn about how to use the DDI, please watch our informational YouTube video at https://youtu.be/L7QOoovsVuU?si=AOsSTF2hREcpQwhA.

For general questions, please email our project team at:
SR37-FairgroundsPIO@portal3.pbid.com.

For more information about the project, please visit https://sta.ca.gov/project/redwood-parkway-fairgrounds-dr-improvement-project/.

For media inquires, please view the project media bar at https://dot.ca.gov/caltrans-near-me/district-4/d4-projects/d4-37-corridor-projects/37-diverging-diamond-interchange-media-resources.

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