NVTA is advancing safety and congestion relief improvements at the SR 29/SR 12/Airport Boulevard and SR 12/North Kelly Road intersections in southern Napa County, also known as the Jameson Canyon interchange. Building on prior planning efforts and an existing 2008 environmental document that selected a tight diamond interchange concept, NVTA is conducting a performance-based alternatives analysis and environmental review in partnership with Caltrans District 4.
The study will explore up to three viable interchange alternatives, including both conventional and innovative designs such as a grade-separated “dogbone” roundabout, while considering multimodal access, context sensitivity, cost-effectiveness, and future growth. The goal of NVTA’s current work efforts is to refine the project footprint and update the environmental clearance to support selection of a preferred alternative and prepare for future design and construction phases.
Location: Southern Napa County, at SR 29 / SR 12 / Airport Blvd and SR 12 / N. Kelly Road
Timeline:
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2024–2027: Environmental Revalidation
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2027–2028: Design
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2028–2029: Right-of-Way
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2030: Construction (pending funding)
UPDATE: 9/17/25
The NVTA Board of Directors approved a contract with Kimley-Horn to study design alternatives at the congested intersection.
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