SR-37/Fairgrounds Dr. Interchange: Construction May 2025, Lane Shifts/Ramp Closures

April 30, 2025

Date: April 30, 2025
Agency: Solano Transportation Authority & Caltrans, District 4-Bay Area
Contact:  Sean Person, Vince Jacala
Phone:  (707) 399-3217, (510) 385-7069

State Route 37/Fairgrounds Drive Interchange – Vallejo
Construction Shifts into Gear – May 2025
Watch for Traffic Lane Shifts/Overnight Ramp Closures

SOLANO COUNTY  – The Solano Transportation Authority (STA), in close coordination with its transportation partner, the California Department of Transportation (Caltrans), has started 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 recently started construction in April 2025. The site is near the Six Flags Discovery Kingdom Theme Park and the Solano County Fairgrounds. Major public impacts to SR 37 and Fairgrounds Drive are scheduled to start in May 2025. In the coming weeks, motorists will begin to see lane traffic shifts, overnight ramp closures, tree removal, signage installation, and various temporary lane closures.

The following construction-related activities are set to happen starting in May 2025.

• Motorists on Fairgrounds Drive at SR 37 should watch for temporary traffic lane shifts.
• Eastbound on and off ramps at SR 37/Fairgrounds Drive will be closed overnight with detours. Closures are scheduled from 10:00 PM until 5:00 AM.
• The westbound off-ramp from SR 37 to Fairgrounds Drive will be closed nightly from 11:00 PM – 5:00 AM.
• The SolTrans bus stop at the on-ramp to Westbound SR 37 will be temporarily relocated a few feet away.

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

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

STA and Caltrans will provide additional project details as soon as information becomes available.

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-improvementproject/.

STA and Caltrans thank the motoring public for its patience and understanding as we work to improve and maintain our state’s highways.

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