Celebrating the Opening of the Bay Area’s First Diverging Diamond Interchange, the SR 37/Fairgrounds Drive Interchange

July 7, 2026 - Vallejo, CA

WMH joined project partners at a well-attended celebration marking the opening of the Bay Area’s first Diverging Diamond Interchange in Vallejo, held near the famed Six Flags Discovery Kingdom. Hosted by the Solano Transportation Authority (STA) in partnership with Caltrans, the City of Vallejo, MTC, Solano County, Six Flags Discovery Kingdom, and local elected officials, the ribbon-cutting recognized a major milestone for the community and the broader North Bay region.

The opening of the Bay Area’s first Diverging Diamond Interchange in Vallejo marks an exciting milestone for the region. This innovative design improves mobility, enhances safety, and delivers significant cost savings by reducing conflict points and minimizing the need for more expensive traditional interchange configurations. It’s a smarter, more efficient solution that maximizes taxpayer dollars while improving how people move through the SR 37 corridor. “The Diverging Diamond Interchange reimagines the State Route 37 corridor as a gateway to the broader Resilient 37 Project, which will address flooding, sea level rise, bay restoration, traffic congestion, and multimodal access,” said Caltrans Director Dina El-Tawansy.

WMH is proud to have led the PA/ED, PS&E, and design services during construction for this transformative project. As Project Manager Carl Gibson shared, “Achieving this milestone takes many years of hard work from all involved, and our engineers are thrilled to see their designs come to life. Congrats on your excellent work! We’re honored to support projects that advance safety, connectivity, and multimodal access across California."

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