State Route 29/California Roundabouts

Project Description/Background

The State Route 29 (SR 29) Northbound First Street Ramps and California Boulevard Roundabouts Project (Project) involves the reconfiguration and construction of three modern roundabouts at First Street and California Boulevard, Second Street and California Boulevard, and SR 29 northbound on and off ramps at First Street.

The purpose of the Project is to relieve existing and future traffic congestion, improve traffic safety and traffic operations, and minimize queues and delay for all three intersections within the Project limits.  Furthermore, the Project includes bicycle and pedestrian facilities to encourage multi-modal forms of transportation.

The Project will accommodate bicycle and pedestrian traffic through a combination of sidewalks, shared use paths and bicycle lanes. Other features of the project include street lighting, landscaping, irrigation and storm drain systems, new side mounted and overhead signs to assist in navigating the roundabouts, the construction of retaining walls, and re-grading to accommodate street design grades and cross-slopes.

The Project will also increase mobility into and out of Downtown Napa through the reversal of First Street and Second Street between California Boulevard and Jefferson Street. Currently, First and Second Streets, between California Boulevard and Jefferson Street operate as a one-way couplet (with east and west-bound traffic separated onto two two-lane streets, rather than allowing two-way traffic on both streets). As part of the Project these streets will be reversed: First Street would become east-bound only, while Second Street would become west bound only, each from the California Boulevard roundabouts to Jefferson Street.

CA Roundabouts Concept

Construction Activities


AT&T and Comcast utilities have been relocated. Pre-project tree removal. 

Coming Up: 

Caltrans is scheduled to perform daytime road work on California Boulevard in Napa between Clay Street and First Street Tuesday, June 11 through Friday, June 14. The southbound lane of California Boulevard will be temporarily closed between Clay and First to accommodate the work and a detour will be in place.

The work is scheduled to take place between 8:00 AM and 5:00 PM starting Tuesday, June 11 and ending at 5:00 PM Friday, June 14. Motorists who wish to proceed northbound on California Boulevard may do so. The northbound lane will remain open.

A detour will be in place (see map). The purpose of the closures is to accommodate work on three roundabouts that will be installed in the area. The temporary daytime southbound lane closures are scheduled to conclude on June 14. Work on the three roundabouts is expected to conclude in 2020.

Project Simulation

The design consultant for the Project, Omni-Means (A GHD Company), prepared a traffic simulation to illustrate how the Project will operate after completion.


Comments and questions may be directed to the Engineering Division email address: [email protected].