Mare Island Causeway Bridge Preventative Maintenance Project

Project Description

The Mare Island Causeway Bridge, originally built in 1934, is a vehicle and pedestrian bridge that straddles the Napa River and serves as the connector between the Greater Vallejo area and Mare Island. In 2016, the City completed an upgrade project on the Bridge, replacing a 50-foot span of bridge timber with steel. The iconic Bridge requires additional maintenance repairs to extend the Bridge's serviceable life and improve pedestrian and driver safety. These repairs are expected to include:

Bridge deck and pile repairs
Sidewalk replacement and ADA improvements
Lighting and handrail repairs
Repainting the Bridge's steel lift span, towers, and historic logo
Deck methacrylate coating (Painting)
Concrete spall and crack repairs
Fender system repair for marine traffic safety
Replacement of underwater anodes

*Read the latest update HERE

Project Location

Budget

$19.8M (Construction Cost) ($22.5M = Grant funding / $3.3M = Local Match)

Project construction Schedule

Mare Island Construction Status

August 4 – October 6, 2025

Weekdays (Monday–Friday): One-lane traffic from 7:00 AM to 5:00 PM, with traffic control provided by onsite flaggers.
Weekends: The bridge will remain fully open with one lane in each direction.

October 7 – March 31, 2027

A new traffic circulation pattern will go into effect as part of the Mare Island Bridge Upgrade Project. To keep things moving smoothly:

The one open lane of the bridge will be used for westbound traffic at all times.
Eastbound traffic from the island to the mainland will need to use Highway 37 at all times.

This temporary change is expected to remain in place through March 31, 2027, as crews work hard to modernize the bridge and enhance long-term traffic flow.

Mare Island Bridge Detour

Public Works staff will be actively monitoring traffic and making adjustments as needed to minimize disruptions.

Motorists are advised to plan ahead, follow posted signage, and drive safely through the work zones. The City encourages all residents to stay informed and help spread the word to minimize disruptions.

The Mare Island Causeway Bridge upgrade is a critical infrastructure initiative aimed at enhancing safety, reliability, and long-term connectivity between Vallejo and Mare Island. The project is expected to continue for approximately 18 months, with completion anticipated by March 31, 2027.

The City of Vallejo appreciates the public’s patience and cooperation during this period of construction. While the short-term inconvenience may pose challenges, the long-term benefits will significantly improve transportation and safety for residents, workers, and visitors.

Let’s build a better bridge—and a better future—together!

Project Documents

If you have questions contact Sam Kumar, Project Manager (707) 648-4432, [email protected].

When will the construction start?
Construction will begin August of 2025 when school on Island is on summer recess.

What is happening with the project right now?
We are starting the final design phase soon and will prepare construction documents to put out for bid.

How long will the construction take?
The construction will last approximately 16 months. The first 13 months of construction will take place on the bridge deck, which may occasionally impact traffic on the bridge. The final three months of construction will be completed on the underside of the bridge which will have no impact on traffic.

Will the construction impact traffic on the bridge?
Traffic will be moderately impacted for the first 13 months of construction. The Contractor will maintain one open lane of traffic at all times. The open lane may be alternated to accommodate the daily flow of traffic (e.g. work, school)

What are the planned hours of operation for construction?
The hours of operation will be determined by the contractor and the City. The expectation is that construction will occur Monday through Friday, during normal business hours.

Do you anticipate any full closures?
Full closures are not anticipated, but in the event a full closure is necessary, the contractor will be asked to only apply a full closure when traffic on the bridge is at its lightest, typically during the night.

What if someone has an emergency on the Island during a full closure?
The contractor will be required to allow priority access for emergency vehicles at all times.

What is the total cost/budget for this project?
$19.8M ($22.5M grant-funded and $3.3M local match funds)

Click here to visit the new project page and see the answers to your questions.

Check out and download the project fact sheet below.

MI Causeway Project Sheet.pdf

City of Vallejo, CA, CA