State Route 37/SR-37- Fairgrounds Drive Interchange- Vallejo Solano Transportation Authority and Caltrans Begin the Next Phase of Construction

Expect Delays on Fairgrounds Drive; See Map with Alternate Routes!

Solano County - The Solano Transportation Authority (STA), in close coordination with its transportation partner, the California Department of Transportation (Caltrans), is continuing 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 divergent diamond interchange. This is the first-ever divergent diamond interchange (DDI) constructed in the Bay Area and only the second-ever constructed on a major highway in California.

What to Expect During Initial Construction Work
Construction at SR 37 and Fairgrounds Drive started construction in April 2025. The site is near the Six Flags Discovery Kingdom Theme Park and the Solano County Fairgrounds. In May traffic in both directions were shifted to the west side of SR 37 and a temporary pedestrian walkway was constructed. Now, STA and Caltrans are moving forward with work to reconstruct the existing Fairgrounds Dr and widen the roadway to accommodate the upcoming Diverging Diamond Interchange.

The following construction-related activities are slated for Monday - Friday during the weeks of January 26, 2026, and February 2, 2026.

Community members and motorists are advised to expect delays and are encouraged to use alternate routes during this time. (Please see map)

• Contractor to reduce northbound Fairgrounds Dr. from SR37 to Gateway Dr. down to one lane, day and night
• During this period, weather-permitting, Fairgrounds Drive will be restriped utilizing single lane closures during daytime hours, 7:00am to 4:00pm.

Motorists should drive with caution in construction zones and expect travel delays. All work is weather dependent.

We appreciate the community's and motorists' cooperation and patience as important work to improve the safety and accessibility of this important project continues!

For general questions, please email our project team at: [email protected].

For more information about the project and to view a video explaining the DDI design, please visit https://sta.ca.gov/project/redwood-parkway-fairgrounds-dr-improvement-project/

For 24/7 traffic updates, please visit 511.org: https://x.com/511SFBay
For real-time information, visit Caltrans QuickMap: https://quickmap.dot.ca.gov
Follow us on X: https://x.com/CaltransD4
Or call 1-800-472-7623, 1-800-427-ROAD for state highway conditions statewide.