Solano Transportation Authority updates Vallejo on SR‑37 Fairgrounds diverging diamond interchange

City staff and Solano Transportation Authority representatives presented an update on the diverging diamond interchange (DDI) planned at Fairgrounds Drive and State Route 37. Nick Burton (STA) described the project as a response to growing congestion — staff said morning peak flows carry about 1,100 vehicles through the interchange — and reviewed how a DDI moves traffic, bicycle and pedestrian accommodations, and outreach activities.

Burton said Caltrans led design work and that the project has a roughly $25 million construction contract with substantial completion planned for June 2026. He described community outreach (traffic advisories, social media, flyers and meetings with community groups), upcoming construction staging (with a key left‑side driving shift during stage 5), and features intended to improve pedestrian and bicyclist safety, including relocated bus stops and center walkways protected by concrete barriers.

Council members asked questions about bicycle protection measures and requested visual material for future presentations. Staff said traffic modeling projects a 25% increase in demand over 20 years and that the DDI would decrease wait times substantially for peak commutes. The presentation included an animated video showing motorist, bicyclist and pedestrian movements through the DDI.